Haibin Wang Hao Tian Rajshekhar Sunderraman An Extended Generalized Disjunctive Paraconsistent Data Model for Disjunctive Information http://arxiv.org/abs/cs.DB/0410053 2004 CoRR cs.DB/0410053 db/journals/corr/corr0410.html#cs-DB-0410053 informal publication