On 26 June 1950, the National Assembly supported a crucial bill written by Milovan Đilas and Tito about "self-management" (samoupravljanje): a type of cooperative independent socialist experiment that introduced profit sharing and workplace democracy in previously state-run enterprises which then became the direct social ownership of the employees. On 13 January 1953, they established that the law on self-management was the basis of the entire social order in Yugoslavia. Tito also succeeded Ivan Ribar as the President of Yugoslavia on 14 January 1953. After Stalin's death Tito rejected the USSR's invitation for a visit to discuss normalization of relations between two nations. Nikita Khrushchev and Nikolai Bulganin visited Tito in Belgrade in 1955 and apologized for wrongdoings by Stalin's administration. Tito visited the USSR in 1956, which signaled to the world that animosity between Yugoslavia and USSR was easing. However, the relationship between the USSR and Yugoslavia would reach another low in the late 1960s. Commenting on the crisis, Tito concluded that: