@inproceedings{BP87Wien,
    AUTHOR = "C. Beierle and U. Pletat",
    TITLE = "On the Integration of Equality, Sorts, and Logic Programming",
    BOOKTITLE = "Proc. 3rd Austrian Conference on Artificial Intelligence",
    EDITOR = "E. Buchberger and J. Retti",
    YEAR = 1987,
    ADDRESS = {Berlin},
    PUBLISHER = {Springer-Verlag} }