Robin Milner. A calculus for the mathematical theory of computation. In Andrei P. Ershov, V. A. Nepomniaschy, editors, International Sympoisum on Theoretical Programming, Novosibirsk, Russia, August 7-11, 1972, Proceedings. Volume 5 of Lecture Notes in Computer Science, pages 332-343, Springer, 1972.
Abstract is missing.