1. Yu. L. Ershov, Theory of Enumerations [in Russian], Vol. 1, Novosibirsk State Univ. (1969, 1974).
2. Yu. L. Ershov, Theory of Enumerations [in Russian], Vol. 2, Novosibirsk State Univ. (1973).
3. Yu. L. Ershov, “Maximal and everywhere defined functionals,” Algebra Logika,13, No. 4, 374–397 (1974).
4. H. Rogers, Jr., Theory of Recursive Functions and Effective Computability, McGraw-Hill, New York (1967).
5. G. Kreisel, “Interpretation of analysis by means of constructive functionals of finite types,” in: Constructivity in Mathematics, A. Heyting (editor), Proceedings of the Colloquium held at Amsterdam, 1957, North-Holland, Amsterdam (1959), pp. 101–128.