@article{DA_1996_3_4_a1,
     author = {V. A. Doiber and A. V. Kostochka and H. Sachs},
     title = {A~very short proof of {Dirac's} theorem on the number of edges in chromatically critical graphs},
     journal = {Diskretnyj analiz i issledovanie operacij},
     pages = {28--34},
     publisher = {mathdoc},
     volume = {3},
     number = {4},
     year = {1996},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DA_1996_3_4_a1/}
}