^Muggleton, Stephen H.; Feng, Cao (1990). Arikawa, Setsuo; Goto, Shigeki; Ohsuga, Setsuo; Yokomori, Takashi (eds.). "Efficient Induction of Logic Programs". Algorithmic Learning Theory, First International Workshop, ALT '90, Tokyo, Japan, October 8-10, 1990, Proceedings. Springer/Ohmsha: 368–381.
^Nienhuys-Cheng, Shan-hwei; Wolf, Ronald de (1997). Foundations of inductive logic programming. Lecture notes in computer science Lecture notes in artificial intelligence. Berlin Heidelberg: Springer. pp. 354–358. ISBN978-3-540-62927-6.
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