Manuel V. Hermenegildo S. Doaitse Swierstra Programming Languages: Implementations, Logics and Programs, 7th International Symposium, PLILP'95, Utrecht, The Netherlands, September 20-22, 1995, Proceedings Lecture Notes in Computer Science 982 Springer 1995 3-540-60359-X db/conf/plilp/plilp95.html