@inproceedings{DBLP:conf/pricai/DelgrandeS98, title = {Reasoning with Sets of Preferences in Default Logic}, author = {Delgrande, James P. and Schaub, Torsten}, booktitle = {{PRICAI}}, pages = {134--145}, publisher = {Springer}, series = {Lecture Notes in Computer Science}, volume = {1531}, year = {1998} }