Van Gelder, Allen (1990-01-01). "Modeling simultaneous events with default reasoning and tight derivations". The Journal of Logic Programming. Special Issue: Logic Programming Applications. 8 (1): 41–52. doi:10.1016/0743-1066(90)90050-F. ISSN0743-1066.
Van Gelder, Allen (1990-01-01). "Modeling simultaneous events with default reasoning and tight derivations". The Journal of Logic Programming. Special Issue: Logic Programming Applications. 8 (1): 41–52. doi:10.1016/0743-1066(90)90050-F. ISSN0743-1066.