1. The Lambda Calculus;Barendregt,1984
2. A. Beckmann, Separating fragments of bounded arithmetic, Ph.D. thesis, Universität Münster, 1996
3. Foundations of Constructive Mathematics: Metamathematical Studies;Beeson,1985
4. Proving programs and programming proofs;Beeson,1986
5. Higher type recursion, ramification and polynomial time;Bellantoni;Annals of Pure and Applied Logic,2000