6Zhenghua Pan. A Logic Deseriptlon on Different Negation Relation in Knowledge. LNCS, Vol. 5227, Springer Berlin / Heidelberg, 2008 : 815 - 823.
7Gerd Wagner. Web Rules Need Two Kinds of Negation//F Bry, N Henze,J Maluszynski. Principles and Practice of Semantic Web Reasoning Prec. Of the 1st International Wrokshop, PPSW3 '03. Springer-Verlag LNCS 2901, Dec 2003.
8Gerd Wagner, Anastasia Analyti, Grigoris Antoniou. Negation and Negative Information in the W3C Resource Description Framework.
9Gerd Wagner, H Herre ,J Jaspars. Partial Logics With Two Kinds of Negation as a Foundation for Knowledge-Based Reasoning//D Gabbay,H Wansing. What Is Negation? Oxford University Press,1999.
