@inproceedings
{Lu:Greenfield:92,
author = {L. Lu and P. Greenfield},
title = {Abstract fixpoint semantics and abstract procedural
semantics of definite logic programs},
booktitle = {Proceedings of IEEE Computer Society 1992
International Conference on Computer Languages},
year = 1992,
publisher = {The IEEE Computer Society Press},
pages = {147-154},
url = {http://www.oakland.edu/~l2lu/pubs/AbstractSemantics.ps},
keywords = {Abstract Interpretation and Logic Programming}
}