Chrysida Galanaki Panos Rondogiannis William W. Wadge An infinite-game semantics for well-founded negation in logic programming. 70-88 2008 151 Ann. Pure Appl. Logic 2-3 http://dx.doi.org/10.1016/j.apal.2007.10.004 db/journals/apal/apal151.html#GalanakiRW08