1. Applebaum, C.H. and J.C.E. Dekker [1970], Partial recursive functions and ω-functions. J. Symbolic Logic 35, 559–568.
2. Barback, J. [1986], Tame models in the isols. Houston J. Math. 12, 163–175. For a correction see the same journal, 13, 301–302 (1987).
3. Crossley, J.N. and A. Nerode [1974], Combinatorial functors. Springer-Verlag, New York.
4. Davis, M. [1958], Computability and unsolvability. McGraw-Hill, New York.
5. Dekker, J.C.E. and Myhill, J. [1960], Recursive equivalence types. U. of California Publications in Math (N.S.), 3, 67–214.