A more formal treatment of a less simple example -- Stationary behaviour of some ternary networks -- Finding the correctness proof of a concurrent program -- On the interplay between mathematics and programming -- A theorem about odd powers of odd integers -- In honour of Fibonacci -- On the foolishness of "natural language programming" -- Program inversion -- The Schorr-Waite graph marking algorithm -- Eliminating the chaff -- Proofs, programs and their development — The axiomatic approach -- Current ideas in programming methodology -- Basic axiomatic definitions -- The multiple assignment statement -- Is sometimes ever better than always? -- A case study in language design: Euclid -- Proof rules for the programming language Euclid -- Verification of Euclid programs -- Specifications and proofs for abstract data types in concurrent programs -- Specification and verification of a network mail system -- From specification to implementation — The formal approach -- Program development by stepwise transformations — The project CIP -- Systematics of transformation rules -- Special transformation techniques -- A study on transformational semantics -- Detailization and lazy evaluation, infinite objects and pointer representation -- Examples for change of types and object structures -- Development of the Schorr-Waite algorithm -- A derivation-oriented proof of the Schorr-Waite marking algorithm -- Languages as tools — Interactive program construction -- Programing languages for reliable computing systems -- Programming methodology and language implications -- Towards a wide spectrum language to support program specification and program development -- Semantics of nondeterministic and noncontinuous constructs -- Notes on type abstraction -- Some theoretical aspects of program construction.