1. The Lambda Calculus, Its Syntax and Semantics;Barendregt,1984
2. A characterisation of computable data types by means of a finite, equational specification method;Bergstra,1980
3. Minimal and optimal computations of recursive programs;Berry;J. Assoc. Comput. Mach.,1979
4. Unique normal forms in term rewriting systems with repeated variables;Chew,1981