1. Maximum matching and a polyhedron with 0,1-vertices;Edmonds;J. Res. Natl. Bur. Stand. (B),1965
2. L.M. Favrholdt, M. Stiebitz, B. Toft, Graph Edge Colouring: Vizing’s theorem and Goldberg’s Conjecture, 2006, No. 20, IMADA, University of Southern Denmark, p. 91.
3. On multigraphs with almost-maximal chromatic class;Goldberg;Diskret. Anal.,1973
4. The NP-completeness of edge-colouring;Holyer;SIAM J. Comput.,1981
5. Asymptotics of the chromatic index for multigraphs;Kahn;J. Combin. Theory Ser. (B),1996