1. D. W. Barron,Recursive Techniques in Programming, Macdonald, London, 1968.
2. Y. Sundblad,The Ackermann Function. A Theoretical, Computational and Formula Manipulative Study, BIT 11 (1971), 107–119.
3. B. J. Cornelius and G. H. Kirby,Depth of Recursion and the Ackermann Function, BIT 15 (1975), 144–150.
4. Algol: 16K Disc Compiler, Technical Publication 4129, International Computers Ltd., London, 1969.
5. Manual for Enhanced CORAL 66 for ICL 1900 Series, Technical Note 15, Royal Military College of Science, Shrivenham, 1973.