was the "free commune". Mikhail Bakunin was the founder of the Spanish collectivist, syndicalist and internationalist workers' movement. Those anarchists tended to follow him and his disciple Ricardo Mella. They were concerned with economic unification and believed that a long transitional period would be necessary during which it would be wiser to reward labor according to the hours worked and not according to need. They envisaged the economic structure of the future as a combination of local trade-union groupings and federations of branches of industry. In 1932, the Spanish anarchist theoretician Isaac Puente published an outline of anarcho-communism and its ideas were taken up by the Saragossa congress of the Confederación Nacional del Trabajo in May 1936. The Spanish anarchist economist Diego Abad de Santillan published an influential treatise on economics, El Organismo Economico de la Revolucion (The Economic Organization of the Revolution). He saw the following: Santillan was to play an important part in the Spanish Revolution. He became a member of the central committee of the anti-fascist militia, a member of the Catalan Economic Council and Economics Minister of the Catalan government. Anarchist historian George Woodcock reports the following: Theoretical economic systems In a chronological and theoretical sense, there are classical—those created throughout the 19th century—and post-classical anarchist schools–those created since the mid-20th century and after. Classical theoretical economic systems Mutualism Mutualism is an anarchist school of thought which can be traced to the writings of Pierre-Joseph Proudhon, who envisioned a society where each person might possess a means of production, either individually or collectively, with trade representing equivalent amounts of labor in the free market. Integral to the scheme was the establishment of a mutual-credit bank which would lend to producers at a minimal interest rate only high enough to cover the costs of administration. Mutualism is based on a labor theory of value which holds that when labor or its product is sold, in exchange it ought to receive goods or services embodying "the amount of labor necessary to produce an article of exactly similar and equal utility". Some mutualists believe that if the state did not intervene as a result of increased competition in the marketplace, individuals would receive no more income than that in proportion to the amount of labor they exert. Mutualists oppose the idea of individuals receiving an income through loans, investments and rent as they believe these individuals are not laboring.