Prolog and deductive databases. - M. Howard Williams; G. Chen; D. Ferbrache; P. A. Massey; S. Salvini; Hamish Taylor; Kam-Fai Wong (Knowl. Based Syst., 1988)

Designing SQUIRREL: An Extended SQL for a Deductive Database System. - K. G. Waugh; M. Howard Williams; Quinzheng Kong; S. Salvini; G. Chen (Comput. J., 1990)