Paul Beame Toniann Pitassi Nathan Segerlind Lower Bounds for Lov[a-acute]sz--Schrijver Systems and Beyond Follow from Multiparty Communication Complexity. 845-869 2007 37 SIAM J. Comput. 3 http://dx.doi.org/10.1137/060654645 db/journals/siamcomp/siamcomp37.html#BeamePS07