H. Abelson and G. J. Sussman with J. Sussman, Structure and Interpretation of Computer Programs.

Kenneth D. Forbus H. Abelson and G. J. Sussman with J. Sussman, Structure and Interpretation of Computer Programs. 124-127 1985 27 Artif. Intell. 1 db/journals/ai/ai27.html#Forbus85