[1]Pulleyblank W R. Fractional matchings and the Edmonds-Gallai theorem. Discrete Appl Math, 1987, 16:51-58

[2]Edward R, Scheinerman, Daniel H Ullman. Fractional Graph Theory. New York: John Wiley and Sonc,Inc, 1997

[3]Anstee R P. An algorithmic proof Tutte’s f-factor theorem. J Algorithms, 1985,6:112-131

[4]Lov´asz L. Subgraphs with prescribed valencies. J Combin Theory, 1970,8:391-416

[5]Heinrich K, Hell P, Kirkpatrick D G, Liu G. A simple existence criterion for (g < f)-factors. Discrete Math, 1990,85:313-317