1. The Vienna Development Method: The Metalanguage;Bjorner,1978
2. Guarded commands, non-determinancy and formal program derivation;Dijkstra;Comm. ACM,1975
3. Principles of OBJ2;Futatsugi,1984
4. The axiomatic basis of computer programming;Hoare;Comm. ACM,1969
5. G. Jeter and D. Dillard, Survey of Formal Specification Techniques, ANSI X3J11 (Language “C”) Ad hoc Committee Report 1983-08-20, also circulated as ISO/TC97/SC5/WG16/N51 = ISO/TC97/SC22/WG10/N51.