life". The dissident discussion group survived until 1962. Other forms of collective community expression and a legally guaranteed academic autonomy (based on the 1958 statute of higher learning) lasted until the 1968 Polish political crisis. The permitted academic discourse was in marked contrast to the treatment afforded workers, whose self-management councils that had spontaneously formed in 1956 were neutralized and brought under control of the party by 1958. In the communist era, because of their class role in the official ideology and leadership's sensibilities, workers enjoyed some clout and a degree of protection of their economic interests, on the condition that they refrained from engaging in independent politics or publicly exerting pressure. Economic reform was attempted when the Sejm created the Economic Council in 1957. The council included the prominent economists Oskar R. Lange, Czesław Bobrowski, Michał Kalecki, and Edward Lipiński. They proposed a market reform, beginning with the granting of greater self-rule and more independent decision-making capability to enterprises, to facilitate their "realization of plan goals". But the recommended economic improvements, despite the self-restraint of the authors, were not compatible with the obligatory at that time heavy-handed centralized economic command system, and the reform effort fizzled out. In October 1957, Poland's Foreign Minister Adam Rapacki proposed a European nuclear-free zone that would include the territories of Poland, West Germany, East Germany and Czechoslovakia. In August 1961, the new Berlin Wall cemented the division of Europe. During 1948–71, the Polish government signed indemnification agreements with a number of West European countries (excluding those considered allies of Nazi Germany), Canada and the United States. The agreements dealt with compensation for the losses incurred by citizens and firms of the countries involved as a result of war events and the subsequent nationalization. The agreement with the U.S. followed the visit to Poland of Vice President Richard Nixon in August 1959 and his talks with Gomułka. It was signed in 1960 and the agreed amount had been paid by the Polish government in twenty installments. The U.S. government thereby assumed responsibility for indemnities resulting from claims filed by U.S. citizens. After the first wave of reform, Gomułka's regime started to move back on their promises. Control over mass media and universities was gradually tightened, and many of the younger and more reformist members of the party were forced out (over 200,000 purged already in 1958, when the PZPR undertook a "verification" of its