1. J. Barwise, Admissible Sets and Structures, Springer, Berlin (1975).
2. Yu. L. Ershov, Definability and Computability, Sib. School Alg. Log. [in Russian], Nauch. Kniga, Novosibirsk (1996).
3. H. Rogers, Theory of Recursive Functions and Effective Computability, McGraw-Hill, Maidenhead, Berksh. (1967).
4. G. E. Sacks, Higher Recursion Theory, Springer, Berlin (1990).
5. Yu. L. Ershov, V. G. Puzarenko, and A. I. Stukachev, “$$ \mathbb{H}\mathbbm{F} $$-computability,” in Computability in Context. Computation and Logic in the Real World, S. B. Cooper et al. (Eds.), Imperial College Press, London (2011), pp. 169-242.