Endre Boros Peter L. Hammer Toshihide Ibaraki Kazuhiko Kawakami Identifying 2-Monotonic Positive Boolean Functions in Polynominal Time. 104-115 1991 conf/isa/1991 ISA db/conf/isa/isa1991.html#BorosHIK91 http://dx.doi.org/10.1007/3-540-54945-5_54