1. Productive sets;Dekker, J. C. E.;Trans. Amer. Math. Soc.,1955
2. On the separability of recursively enumerable sets;Mučnik, A. A.;Dokl. Akad. Nauk SSSR (N.S.),1956
3. Creative sets;Myhill, John;Z. Math. Logik Grundlagen Math.,1955
4. Recursively enumerable sets of positive integers and their decision problems;Post, Emil L.;Bull. Amer. Math. Soc.,1944
5. Gödel’s theorem and the theory of algorithms;Uspenskiĭ, V. A.;Dokl. Akad. Nauk SSSR (N.S.),1953