@ARTICLE{Schmittetal92a,
        AUTHOR    = {Ch.Beierle and U.~Hedst\"{u}ck and U.~Pletat and 
                      P.~H.~Schmitt and J.~Siekmann},
        JOURNAL   = {Journal of AI},
        PAGES     = {149--191},
        TITLE     = {An order-sorted logic for knowledge representation},
        VOLUME    = {55},
        YEAR      = {1992}
}