1. An Initial Algebra Approach to the Specification, Correctness, and Implementation of Abstract Data Types;Goguen,1978
2. A Birkhoff variety theorem for continuous algebras;Adamek;Algebra Universalis,1985
3. Generalization of the concept of variety and quasivariety to partial algebras through category theory;Andreka,1983
4. also Math. Inst. Hung. Acad. Sci., preprint No. 5, 1976.
5. A general axiomatizability theorem formulated in terms of cone-injective subcategories;Andreka,1981