IFIP Working Conference, 1977 Formal Description of Programming Concepts, North-Holland Pub. Co. 1978

• Anderson, E.R., F. C. Belz, and E. K. Blum, (1977) Anderson, E.R., F. C. Belz, and E. K. Blum, "Issues in the Formal specification of Programming Languages
• Joseph Goguen. (1979) Joseph Goguen. "Abstract errors for abstract data types"