Yuan Liu
Null Values in Definite Programs
ICLP, 1990.
@inproceedings{NACLP-1990-Liu, author = "Yuan Liu", booktitle = "{Proceedings of the North American Conference on Logic Programming, 2 Volumes}", isbn = "0-262-54058-4", pages = "273--288", publisher = "{MIT Press}", title = "{Null Values in Definite Programs}", year = 1990, }