@workingPaper{BaaderBürckertNebelNuttSmolka_1991,
title={On the expressivity of feature logics with negation, functional uncertainty, and sort equations},
author={Baader, Franz and Bürckert, Hans-Jürgen and Nebel, Bernhard and Nutt, Werner and Smolka, Gert},
doi={http://dx.doi.org/10.22028/D291-24990},
year={1991}
}