@article{GDZPPN002218569, title = {Die chromatischen polynome Unterringfreier Graphen.}, journal = {Manuscripta mathematica}, volume = {12}, year = {1974}, pages = {223-234}, zbl = {0293.05113}, url = {http://dml.mathdoc.fr/item/GDZPPN002218569} }
Braun, K.; Kretz, M.; Walter, B. Die chromatischen polynome Unterringfreier Graphen.. Manuscripta mathematica, Tome 12 (1974) pp. 223-234. http://gdmltest.u-ga.fr/item/GDZPPN002218569/