Note on a test example for ALGOL60 compilers by D.E. Knuth.- The assignment to a type procedure identifier in ALGOL60.- The meaning of names in PL/I.- Defining a language in its own terms.- Note on some problems concerning the PL/I manual and its re-writing.- Definable operations in general algebras, and the theory of automata and flowcharts.- Formalization of storage properties.- On the formal definition of programming languages.- A formal definition of a PL/I subset.- Mathematical semantics and compiler correctness.- Towards a mathematical theory of processes.- From comments arising from a lecture in Amsterdam, June 1972.- The semantics of parallel processing.- Nondeterministic functions and the semantics of CSP.- Nondeterministic programs : An example.- A model of nondeterminism: Indexed sets and their equivalence.