Media type: E-Article Title: Lecture Notes in Computer Science: Defining variants of default logic: A modal approach Contributor: Giordano, Laura imprint: Springer Berlin Heidelberg, 1993 Published in: Lecture Notes in Computer Science Language: Not determined DOI: 10.1007/3-540-56804-2_6 ISSN: 0302-9743; 1611-3349 Origination: Footnote: