Ton Kloks Dieter Kratsch Computing a Perfect Edge Without Vertex Elimination Ordering of a Chordal Bipartite Graph. 11-16 1995 55 Inf. Process. Lett. 1 db/journals/ipl/ipl55.html#KloksK95 http://dx.doi.org/10.1016/0020-0190(95)00027-A