1. J. W. de Bakker,Correctness proofs for assignment statements (Report IW 55/77), Mathematisch Centrum, Amsterdam, 1977.
2. J. W. de Bakker,Mathematical theory of program correctness, Prentice-Hall, Englewood Cliffs, 1980.MR 82g: 68016
3. P. Burmeister andJ. Schmidt, On the completion of partial algebras,Colloq. Math. 17 (1967), 235–245.MR 37 # 125
4. P. Burmeister,Partial algebras — Survey of a unifying approach towards a two-valued model theory for partial algebras (Preprint Nr. 582), Techn. Hochschule, Darmstadt, 1981.
5. E. W. Dijkstra,A discipline of programming, Prentice-Hall, Englewood Cliffs, 1976.Zbl 368. 68005