1. Aarts, C.J.: Galois connections presented calculationally. Master’s thesis, Department of Mathematics and Computing Science, Eindhoven University of Technology (1992)
2. de Bakker, J.W.: Semantics and termination of nondeterministic recursive programs. In: Michaelson, S., Milner, R. (eds.) Automata, Languages and Programming: Third International Colloquium, pp. 435–477. Edinburgh University Press, Edinburgh (1976)
3. Berghammer, R., Zierer, H.: Relational algebraic semantics of deterministic and nondeterministic programs. Theoretical Computer Science 43, 123–147 (1986)
4. Colloquium Publications;G. Birkhoff,1967
5. Lecture Notes in Computer Science;M. Broy,1979