1. Choosability in graphs;Erdős,1979
2. Progress on the Hall-number-two problem;Eslahchi;Australasian J. Combin.,2000
3. Characterization of graphs with Hall number 2;Eslahchi;J. Graph Theory,2004
4. The list chromatic index of a bipartite multigraph;Galvin;J. Combin. Theory B,1995
5. H. Gröflin, Feasible graph coloring and a generalization of perfect graphs, Manuscript, University of Fribourg, 1992