The First Stafford Beer Memorial Lecture July 8, 2007

The Viable System Model and its Application to Complex Organizations

Allenna Leonard, Ph.D.

The Complementary Set

allenna_leonard@yahoo.com

http://www.allennaleonard.com

Abstract

Stafford Beer’s Viable System Model is the best known of the many cybernetic models he constructed over a career spanning more than fifty years. He explored the necessary conditions for viability in any complex system whether an organism, an organization or a country. Although the model was first applied in his work in the steel industry, many further applications were made during his later work as a consultant. The best known of these was when he was invited by President Salvadore Allende of Chile in 1970 to model the social economy of that country. That experiment was brutally cut short in 1973 by the CIA assisted coup during which Allende was killed and Pinochet’s dictatorship installed.

The model itself draws on mathematics, psychology, biology, neurophysiology, communication theory, anthropology and philosophy. It was first expressed in mathematical terms in ‘The Cybernetic Factory’; next it was described in neurophysiological terms in ‘Brain of the firm; and finally according to logic and graphic presentation in Heart of Enterprise and Diagnosing the System for Organization. This last version is the one that is most accessible. It enables people to address organizational issues in a way that skirts the usual categories and organization charts and gets down to the actual necessary functions, no matter who is performing them.

With this model people can diagnose or design an organization; making sure that the principle homeostats, management functions and communications channels are in place and can function effectively. A crucial aspect of the VSM is that it is recursive; that is that the same relationships can be traced from the shop floor to the corporation or from the village to the country. Two examples will be discussed: a small business and the Chilean work from the 1970’s. It is hoped that this will encourage people to imagine a world that works much better than it does now and where management is not defeated by complexity.

Introduction

I am pleased to have been invited to give the first Stafford Beer Memorial Lecture to the World Multiconference on Systemics, Cybernetics and Informatics in Orlando this year. Stafford himself gave a keynote to this body in 1998 talking about his own work and bracketing it with that of his mentor, neruocybernetician Warren McCulloch (McCulloch, 1989) and the work of Candace Pert, the author of Molecules of Emotion (Pert, (1997).

The first thing to say about Stafford was that he was a big man – both in stature and in the scope of his ideas. He was also a polymath – a scientist who painted, wrote poetry, taught yoga and cooked a delicious Yorkshire pudding. His did not leave his values behind when he took on assignments. He firmly believed that science was for the benefit of the people and that scientists themselves were not exempt from ethical concerns about how their work was used. He engaged in projects from the theoretical to the practical. We worked together on a UNDP project in Uruguay that was to include an operations room. (Beer, 1989)) There were deep questions about the nature of ‘true community participation’ and nuts and bolts considerations like whether a voice recognition system could be used for electronic communications. The answer to this particular question was somewhat of a surprise. We tested the software in Canada and found it to be effective in differentiating among the different voices. When we took it to Uruguay, however, this capacity disappeared. We hadn’t realized how much more variety there was in Canadian accents and speech patterns than there was among people speaking Uruguayan Spanish.

Stafford believed that no human issue was to complex to be addressed whether it was a company or a country. The trick, he said was to look for the invariances and the key homeostats that allowed a useful model to be built.

Stafford’s development, like that of other Englishmen of his generation, was profoundly influenced by WWII. First, when he arrived at university as a sixteen year old, he was one of a small number of students studying with two faculties – that of the University of London where he had matriculated and that of University College of Wales at Aberystwyth where they relocated during the war. This gave him, a philosophy major, access to Old English, new physics, mathematics, statistics and psychology. By his eighteenth birthday he was in the Army where he served with the Gurkhas, eventually as Staff Captain Intelligence. His work led him to apply his studies in mathematics and logic to what he later realized belonged to the new interdisciplinary field of operational research. When he returned to the university after his service, he found that the interdisciplinary track he had followed in university and in the army was not to result in the advanced standing several of his professors invited him to pursue but a requirement that he begin again on probation and stay firmly within the boundaries of his selected major. Not surprisingly, he rejected this demand and set off into industry, where there was interest in applying OR to domestic uses.

He joined a branch of United Steel, working first as a production controller. After reading Norbert Wiener’s book Cybernetics, he wrote to say, “I think I am a cybernetician”. This led to contacts and friendships in the field with Wiener himself, Warren McCulloch, Russell Ackoff and Heinz von Foerster in the United States and with Ross Ashby, Grey Walter, Gordon Pask and others in the UK. Eventually this led to his inaugurating a Department of Operational Research and Cybernetics employing seventy professionals at United Steel. While there, he began experiments mapping various properties of the human nervous system onto their industrial counterparts. You can see his electro-encephalogram of a steel mill and other artifacts in the Stafford Beer Collection at Liverpool John Moores University. Other experiments were documented in early papers, beginning in the 50’s. A number of these, including ‘the Cybernetic Factory’ the most complete early mathematical formulation of the VSM, are collected in the book “How Many Grapes Went Into the Wine” (Harnden, R. and Leonard, A. eds. 1994).

Ross Ashby’s work on requisite variety provided important insights to this early work. (Ashby, 1956) Ashby defined variety as the number of possible states of a system. The Conant-Ashby theorem is perhaps the best known and most succinct of his formulations. (Conant, R. and Ashby, W.R. 1970) It says every good regulator of a system must contain a model of that system’; that is to say; the regulator needs to have as much variety at its disposal as does the system to be regulated.

The simplest variety containment strategy is one-to-one, such as the eleven members of a football team ranged against eleven similar opponents. This isn’t efficient in most circumstances, so a good regulatory model amplifies the variety of the regulator to a one-many ratio, sometimes through very simple structural designs that regulate group behavior. Traffic control is an everyday example: cars going one way stay on their half of the road and stop or go at intersections according to the traffic light. Other approaches attenuate the variety of the system so that the model includes only those matters of interest to the regulator. ‘What’ is of interest depends on the situation, and how much can be left to a system’s capacity for self-organization. Dee Hock’s design of a chaordic structure for Visa is a good example of centralized regulatory apparatus pared down to the minimum.

Sometimes complex situations can be described by building out from one’s area of concern and looking at the policy implications. Stafford built a model of health care for the Ontario government in the ‘70’s that looked at the balance between the pools of people who were well and those that were ill. (Beer, 1979) From that deceptively simple distinction, he began to move outward looking at ways to retain people in the ‘well’ category on the one hand and ways to return them from the category of the ill to that of the well on the other. When one is considering the health of a person, rather than any other of the many attributes of an individual, the pool of the well has a great deal less variety for purposes of health care delivery than the pool of the ill. This suggests that spending a tiny percentage of the budget on public health is loading the wrong side of the equation.

Stafford made hundreds, maybe thousands of models. He was especially fond of a process he diagramed in his yo-yo model. (Beer, 1966) In it, a metaphor between an organizational situation and a scientific one was tested to see if it was logically consistent enough to be a simile. If that worked, the next step was a homomorphic and perhaps an isomorphic mapping and a mathematical description. Models flow from distinctions; selections of characteristics important to the question at hand. Stafford said models aren’t ‘true’ or false; they are more or less useful, depending on the purpose of the person using it. A model airplane may or may not fly, while computer models of airplanes provide the specifications for their manufacture. A good model, for the purpose, has requisite variety and captures the salient relationships. An inadequate one lacks requisite variety and misses important aspects of the situation, leading to unintended consequences. Stafford was not known for turning a blind eye to the persistence of unintended consequences: “the purpose of a system is what it does” became one of his aphorisms.

Cybernetic models differ from others in that they focus on relationships that are dynamic. Ross Ashby showed that only a few simple decision rules in a model could lead to complex interactions. Often they centered the maintenance of equilibria called homeostasis with the ‘mechanisms ‘referred to as homeostats. A complex organism, like the human body sustains itself through the operation of a great many homeostats. Body temperature, electrolyte balance, blood sugar and many others operate for the most part out of our conscious awareness although if they fail, they do intrude on consciousness and the consequences can be serious.

Stafford was especially interested in the operation of homeostasis in human organizations. He postulated that the first consideration of an organism or an organization, such as a business or a city, was to survive. To do so required that its essential variables be maintained within acceptable limits. Often he was able to point to a single homeostat as a bellwether measure – if this aspect was in equilibrium, the rest of the situation would remain stable. He defined viability as able to maintain an independent existence. In the business world, that means selling a product or a service that a customer in its environment wants to buy for more than the cost of producing it. All the management structure in the business is there to support these transactions. This is the basis for his Viable System Model. (Beer, 1979, 1981, 1985) It describes the necessary conditions for viability.

The Viable System Model

System One and Its Environment

Every system, often described by a circle, operates in an environment, described as an amoeba shape to denote that its boundaries are not fixed. It can be further divided by making distinctions between, say, the transactional environment and the contextual environment or the natural environment and the social environment. The system is buffeted by events in the environment and it must have the capacity to adapt in order to cope with them. The success of that adaptation depends on the quality of the system’s intelligence about the environment and the resources available to make use of that intelligence. Management, whether by a set of bosses or by self-managed teams, is the function that metabolizes the intelligence about the environment and the energy of the system to act upon it. It is shown as a small square in the operation. The square needs to remain relatively small so that it does not use up the resources needed by the system to engage its environment. Note that this is the same function that is used by a single cell organism as it senses and moves toward a food source. It also has homeostats that attempt to keep essential variables – enough food, a comfortable temperature, etc. within healthy limits.

A business or a government is much more complex than a single cell organism. It has many more essential variables to consider and many more connections with its environment to monitor. The transactional environment of an organization includes its customers or clients, its suppliers, its regulators, its employees and its other stakeholders. Its contextual environment includes both direct influences like competitors and indirect influences such as available complementary technology and public taste. Stafford’s own applications of the VSM often showed environmental factors in some detail, including communications taking place wholly within the environment that affected the system.

A typical business will make several products or will offer them in different markets. These operate in parallel, sharing more or less overlapping environments and stronger or weaker communications among them. Stafford called them System One activities. What makes them viable systems is that any of them could be sold off as independent businesses active on its own. Since they each maintain relations with their own particular environments, they are closest to the action and do best when they can exercise autonomy in meeting the demands they see in their markets.

The homeostat that balances the operations with their markets along the horizontal axis of the model is the first aggregate homeostat in the VSM.

System Two

However, that autonomy has limits. Any time you have two or more activities being operated together, the possibility exists for them to get out of synch with each other or get in each other’s way, leading to oscillation in the larger system. A System Two exists as a service to damp this oscillation and to coordinate common services for consistency and efficiency. Here’s a short list of the services in a complex organization that may come under System Two:

Access for disabled persons

Accounts payable

Accounts receivable

Catering

Certifications

Cleaning

Computer/it services

Courtesy expectations

Diversity promotion

Documentation

Dress code

Employee assistance and benefit programmes

Employee handbooks

Energy efficiency

Hazardous materials rules

House style

Insurance

Landscaping

Maintenance

Mailroom

Orientation

Parking

Personnel

Printing

Purchasing

Safety

Scheduling of common facilities

Security

Tax compliance

Telephone networks

Training in existing practices

Travel

Use of shipping and handling facilities

Vacation schedules

There are several things to note about this list. First, none of these activities earns a penny, although doing them efficiently rather than inefficiently may save money. Second, depending on particular circumstances, most organizations of any size will be engaged in most of them, and perhaps others as well. They do not, after they are established, require much in the way of executive attention unless there is a radical change in the situation. They are administrative, and exist so that things run smoothly. Some are mechanical, some administrative, some physical, some formal, and some informal but together they absorb a lot of variety so that people don’t have to reinvent the wheel. Finally, none of them are viable systems in their own right for this organization, although in these days of outsourcing, provision of some of these services, like catering or cleaning or security, might be viable systems in someone else’s company.

System Three

There are executive functions and decisions to be made, given that this particular organization has more than one operation. The viable organization should be run in the interests of the whole, which may not always be the most advantageous for one or more of the parts at any given time. This circumstance leads to resource bargaining among the parts so that demands can be met, opportunities seized or threats avoided. In an organism, this resource allocation usually happens smoothly. More blood flow is directed to the legs when running and to the stomach when digesting a big meal. This doesn’t necessarily happen in an organization. There may well be competition among the parts for resources of management attention, additional personnel, finances and advertising campaigns. Furthermore, there are laws that must be complied with and contracts that must be negotiated and honoured. Management accounting, budgeting and production control are typical of functions provided by System Three.

System Three Star

From time to time, System Three will see a need to probe more deeply into System One operations to satisfy particular needs or to cope with a disaster like a flood or a blackout. System Three Star fulfills this need for an audit channel that can delve into detail without taking over and micro managing. The financial audit is the most obvious example, but there could be an energy audit, a security audit, an IT compatibility audit, a study of customer complaints and others. Sporadic employee satisfaction surveys and needs analyses are other examples.

Taken together, the management functions of Systems One, Two, Three and Three Star account for the inside and now of an organization, operating in the present tense. Note that the only direct connection to the environment exists in the linkage between it and the System One operations. Note also that these are functions, not names on an organization chart. It is possible, even likely, that an individual could play a role in delivering a product or a service to a customer and in managing that operation. System Three often includes representatives from management at System One and almost everyone enacts roles in System Two, at least by observing the protocols.

System Four

Although time lines vary from seconds to decades, organisms and organizations need some capacity to anticipate the future and prepare for it. System Four’s role is to observe the anticipated future environment and its own states of adaptiveness and act to bring them into harmony. To do so, it must also have a clear picture of System Three’s present state so it can offer alternative paths from the present to the future. Changes in the natural, social, economic, technological and political environments and their interactions determine the conditions that the organization must be ready to face if it is to survive. An organization must keep its information about future developments flowing and must act internally to be ready for them. This involves not only working to improve its present products -we all know about the buggy whip syndrome – but also to develop new ones to meet the needs of emerging markets. Recruitment, staff development, benchmarking, participation in trade shows and conferences, market research and lobbying are concerned with learning about and affecting the outside and future. Research and development, strategic planning, borrowing policies and marketing use that knowledge to make internal modifications to be ready for coming changes. An effective System Four engages in continuous dialogue between its model of the anticipated future and its model of itself.

The Three/Four Homeostat

Maintaining a good balance between System Three’s concern with the day to day running of affairs and System Four’s concentration on the anticipated future is a challenge for every organization. It is difficult, because the balance isn’t the same for every organization, the same organization at every time or every part of the same organization. A great deal depends on the rapidity of technological advance and changing tastes in each industry. For the high tech world, getting the first working prototype developed and to market means that the proportion of energy directed toward System Four will be a high one. In a mature industry, such as forestry, supply and demand might remain fairly constant for years – until a new insect arrives on the scene or tariffs make exports uncompetitive.

As a general rule, Stafford mapped out trajectories for new products along an S curve. One had to have technology B up and ready to go as the demand for technology A began to flatten. His use of real-time monitoring of key indices was another way of keeping alert to change. If each System One reported on around ten measures each day, then the time series could be mapped and examined using statistical filtration techniques. If they were all within expected ranges, operations continued as normal. If a value was recorded that was out of range, then it would be examined carefully. Some would be recording errors, random variations or transients. Others would represent slope or step changes in that index and they required immediate attention. Selecting and tuning the indices to be monitored required a good knowledge of the system.

If we go back to the homeostat between the well and the ill, we can reflect on our own experience of going for a basic medical check-up. If no concerns are raised, a relatively small number of measurements are made: weight, blood pressure, temperature and blood tests for diabetes, anemia and cholesterol. Eyes and ears are examined and abdomens pressed. If everything is ‘normal’ no further work is done but if not, that aspect is pursued in more detail.

The Three/Four Homeostat is the second of the three important aggregate homeostats in the VSM.

System Five

Closure is provided by System Five. Its active job is to monitor and adjust the Three/Four Homeostat. Its broader function embodies identity and coherence and underwrites the viability of the whole. An organization is faced with many requirements for choices and decisions, and some technical help is available to make good ones. This is where the emphasis is on doing the right thing rather than doing things right. But, all ‘good’ choices aren’t good for or compatible in every organization and even doing the ‘right’ thing for reasons that are wrong or unclear puts an organization at risk. Questions such as ‘what business are we in?’ or ‘who are our clients?’ must be asked continually to avoid losing touch with oneself and one’s markets. Today, organizations are making products while busily researching their transitions to a service economy. To be sure, much of the actual exploration is carried out in System Four, but its work has to be consistent with the evolving identity of the organization.

Taken together, the organization’s Five/Four/Three represents the metasystem of the One/Two/Three present activities.

All the management functions, One through Five, represent the vertical variety management that balances the horizontal variety between the System Ones and their environments. This is the last important aggregate homeostat in the VSM.

Recursion

Perhaps the most useful feature of the VSM is that its structure and communications channels are repeated from the smallest productive unit to the largest. It is a recursive model in which parts are nested within the whole like a series of Russian dolls. This allows for a great deal of economy in the analysis as well as easy comparisons among System One through Five’s activities along both horizontal and vertical lines. By convention, the most comprehensive recursion is referred to as recursion zero and subsystems by one, two, etc. If we think back to the list of activities under the heading of System Two, we will see that they attach to different levels in the VSM. Functions like security, common use of physical resources like meeting rooms or loading docks and parking are likely to be site specific. Others such as accounting, branding, recordkeeping, tax compliance and personnel functions are often done in common across the whole legal boundary of the organization, although some sensitivity to local variety is needed. Questions should be frequently asked about whether the location of these administrative functions is appropriate under changing conditions or when operations are initiated in new jurisdictions or with different types of employees.

Let’s take a brief look at a small business – a mom and pop gift shop that has two operations: a section that buys and resells products run by Mom and another, run by Pop that sells work from its onsite pottery. Each of these also has two operations: sections for year round merchandise and for seasonal merchandise in the one and useful and decorative pottery in the other. Mom and Pop play roles in all five systems at recursion zero – the whole gift shop - and each pitches in to help the other at recursion one. System Two’s duties are divided between the two recursions with accounting, scheduling, shipping and security happening at recursion zero and safety, energy efficiency, cleaning and maintenance occurring at recursion one. System Four will also be highly differentiated as the environment for new developments and changing tastes is not the same for the two lines of business, or, necessarily for the product lines at recursion two. System Five is more tacit than explicit in such a small business but it is strong nonetheless. This small business operates with the same functions as a much larger business or non-profit, although probably less attention needs to be paid to maintaining communications channel capacity.

The General Picture

Although I’ve been talking so far about organizations in the business world, government, non-profit and informal or non-institutional providers of goods and services share similar concerns with a larger number of variables and broader criteria of success. The examples so far have also concentrated on organizations with a single legal boundary but that is not necessary and many participants contribute to the viability of larger entities up to and including whole countries.

The Work in Chile

In 1970 Stafford received an invitation from President Salvadore Allende, the newly elected socialist president of Chile. The assignment led to his becoming scientific director of an effort to organize the social economy of the country and to advance Allende’s agenda of a peaceful road to socialism which included production directed to filling the needs of citizens, worker participation in decision making and resilience against external buffeting. The project was called Cybersyn for cybernetic synergy. The life of the project was less than two years from its initiation to the overthrow of the Allende government. Despite its short life, rapid progress was made on realizing Allende’s goals of integrating the national economy and learning how to make worker participation a reality. (Medina, 2006)

Chile at that time, like many Latin American countries, historically had a large state-owned sector of the economy, supplying energy, products of heavy industry and transportation. This occurred because the scale of operations was not large enough to make investments there profitable for private concerns but too broad to be satisfied by what small producers might provide. These were grouped under an entity called CORFO. When Allende nationalized additional sectors of industry, their management was brought under the CORFU umbrella at a rapid rate. (Schwember, 1977)

There were several features of the project. The first was the use of the VSM. Twelve levels of recursion were identified from the individual worker to the country as a whole. In practice, Cybersyn focused on the levels of the product line, the sector, the branch, (there were four – perishable consumables, non-perishable consumables, heavy industry and machinery) and CORFU itself. For prototyping purposes some firms were modeled and training was piloted for firms to provide meaningful worker information and participation and to differentiate between their roles and knowledge bases and those of the experts.

Cybersyn wasn’t only a technical project. Stafford wrote up and made some experiments in participation that later led to the development of his Team Syntegrity process. Folk singers and artists were approached for their contributions to the vision of the Allende government. Stafford and Angel Parra collaborated on an initial effort – a song called Litany for a Computer and a Baby About to Be Born. It was a time of great hope and excitement.

Much of what would be considered standard operational research was included too. Quantified flow charts were prepared for a given product line from the raw materials, production processes, containers and order fulfillment to distribution to the customer.

From six to twelve indices were established for each product line. Values that were outside the normal range were fed from the System One units to System Three for examination. The determination that they were out of range was made by a set of programs based on the Bayesian statistics of Harrison and Stevens. Systems One to Three had a time period within which to address the changes. If the issue could not be resolved within that time, that was an indication that a more comprehensive picture was needed and it was fed up to the next level. In this way, issues like shortages could be addressed for the whole product line and supplies moved around among them.

An operations room facilitated oversight at System Five. This was, literally a room with from seven to ten chairs where decision makers could meet. Its walls had multiple screens: one its VSM, at several levels of recursion; other set contained data from quantified flow charts; a third held outputs from various indicators and a fourth had Forrester’s Dynamo output. Others showed maps and pictures of facilities and computer plots of trends.

Information was fed to the operations room on a daily basis – what Stafford called bogus real time. Erroneous reporting afterward stated that this couldn’t have been accomplished because the Chileans could not have mounted a sufficiently large data bank. The economy of Cybersyn was that it didn’t require a data bank. Only ‘out of normal range’ results from ten or so indices at each level were reported. Some of the data from remote areas actually traveled to a telex machine by donkey. All this is a reminder that intention and ingenuity can accomplish a great deal.

All these processes were focused on Systems One to Three. System Four ran in two tracks. The traditional planning processes were continued while experiments were made with Forrester’s System Dynamics. The experiments with Dynamo were not conclusive for two reasons. The whole Chilean situation was changing too fast along too many parameters and the experiments were cut short by the coup.

Despite difficulties, the project enjoyed considerable success. Stafford later wondered if it had been too successful. The government had, because of its superior information handling capacity, survived the gremmio strike, massive shortages and other perturbations. This may have contributed to the high level of bloodshed that followed in the CIA inspired coup. The extent of violence was a surprise; it had not been part of Chilean history before.

The Cybersyn project remains today the broadest application of cybernetics to government and the management of affairs. No country since has been so willing to try such an innovative approach although the less than satisfactory performance of most governments would lead a reasonable person to wonder why not something new shouldn’t be tried.

The return of democracy to Chile, especially since the death of Pinochet, has brought a new interest in exploring that chapter in its history. Some of you may be interested to know that a documentary on Cybersyn is being made by Chilean filmmaker Enrique Rivera and his team. Stafford described the story in the 2^nd Edition of “Brain of the Firm” (Beer, 1981) and1n “Platform for Change” (Beer1975). In addition Hermann Schwember (Schwember, 1975) wrote a paper describing the project from the perspective of an inside participant and Eden Medina (Medina, 2006) has published her research.

Conclusion

Governments and international bodies don’t face any fewer challenges now than they did in the 70’s. It could be argued that the world has not become less but more complex since that time. The situation that Allende addressed, that of making a country work for all its people, has not been resolved in many places. Indeed, the income disparity within and among countries has grown. Post conflict states continue to try to find equilibrium using low variety models of their situations and antecedents.

Moreover, a high proportion of our global system problems are only partially addressed by official bodies with traditional lines of authority. A hierarchy based on comprehensiveness of information is needed and could be designed using the VSM. For example, measurements tell us that sea level is rising and projections based on glacial melt tell us that the trend is likely to increase. We must prepare to address this problem and others such as the health care costs of air pollution that are often are experienced outside the jurisdiction where it originated. Policies that deal with the interaction of our natural and social environments fall far short of what is needed for our human societies to remain viable. It is certainly a time to try to communicate how useful and necessary our tools can be. The integration of operational research and its sophisticated statistics, simulations, participation, culture change and the emotive power of the arts could make a difference today, as they might have done in Chile without CIA intervention. The experiment is worth pursuing.

References

Beer, S. (1966) Decision and Control. Chichester: John Wiley & Sons, P. 118.

Beer, S. (1975) ‘Fanfare for effective freedom’ in Platform for Change. Chichester: John Wiley & Sons. pp. 421-453.

Beer, S. (1979) ‘ In search of health’. Unpublished report.

Beer, S. (1981) Brain of the Firm, 2^nd Ed. Chichester: John Wiley & Sons,

Beer, S. (1985) Diagnosing the System for Organizations. Chichester: John Wiley & Sons.

Beer, S. (1989) ‘ National government: disseminated regulation in real time or ‘How to run a country’ in Espejo, R. and Harndon, R. Eds. The Viable System Model: Interpretations and Applications of Stafford Beer’s VSM. Chichester: John Wiley & Sons

Beer, S. (1994) ‘The Cybernetic Factory’ In Harnden, R. and Leonard, A. Eds. How Many Grapes Went into the Wine. Chichester, Joh. International Journal of Systems Science n Wiley & Sons.

Conant, R. and Ashby, W.R. (1970) ‘Every good regulator of a system must be a model of that system’, Vol. 1. # 2 pp. 89-97.

McCulloch, W.S. (1989) Collected Works, Ed. R.McCulloch. Salinas, CA: Intersystems

Press.

Medina, E. (2006) ‘Desiging freedom, regulating a nation: socialist cybernetics in Allende’s Chile’. In Journal of Latin American Studies Vol. 38. Pp 571-606.

Pert, C. (1997) Molecules of Emotion. New York: Scribner.

Schwember (1977) ‘Cybernetics in government: experience with new tools for management in Chile 1971-1973’. In H. Bossel, Ed. Concepts and Tools of Computer Based Policy Analysis, Vol. 1. Basel, pp. 136.