1. Proof rules dealing with fairness;Apt,1982
2. A Cook's tour of countable nondeterminism;Apt,1981
3. Countable nondeterminism and random assignment;Apt,1982
4. A continuous semantics for unbounded nondeterminism;Back;Theoret. Comput. Sci.,1983
5. Recursive procedures;de Bakker;Mathematical Centre Tracts,1971