エミール・ポスト
1936, "Finite Combinatory Processes - Formulation 1," Journal of Symbolic Logic 1: 103-105.
1943, "Formal Reductions of the General Combinatorial Decision Problem," American Journal of Mathematics 65: 197-215.
1944, "Recursively enumerable sets of positive integers and their decision problems," Bulletin of the American Mathematical Society 50: 284-316.