Mondes et programmation en logique. - Hervé Kauffmann; Alain Grumbach (SPLT, 1985)

MULTILOG: Multiple Words in Logic Programming. - Hervé Kauffmann; Alain Grumbach (ECAI, 1986)

Representing and Manipulating Knowledge within "Worlds". - Hervé Kauffmann; Alain Grumbach (Expert Database Conf., 1986)