Logics for artificial intelligence: Raymond Turner, Ellis Horwood Ltd., West Sussex, England, First Printing 1984, Second Printing 1985.

Manton M. Matthews Logics for artificial intelligence: Raymond Turner, Ellis Horwood Ltd., West Sussex, England, First Printing 1984, Second Printing 1985. 89-90 1988 2 Int. J. Approx. Reasoning 1 http://dx.doi.org/10.1016/0888-613X(88)90007-2 db/journals/ijar/ijar2.html#Matthews88