1. On the correctness of refinement steps in program development;Back,1978
2. Procedural abstraction in the refinement calculus;Back,1987
3. A calculus of refinements for program derivations;Back;Acta Inform.,1988
4. Procedures, parameters, and substitution in the refinement calculus;Cavalcanti,1997
5. A Discipline of Programming;Dijkstra,1976