1. An initial algebra approach to the specification, correctness and implementation of abstract data types;Goguen,1978
2. Equational partiality;Benecke;Algebra Universalis,1983
3. Putting theories together to make specifications;Burstall,1977
4. The semantics of clear, a specification language;Burstall,1980
5. Une approace logique des theories definissable par limites projectives finies;Coste,1976