@article{IVM_1982_3_a4,
     author = {V. A. Molchanov},
     title = {Semigroups of graph colorings},
     journal = {Izvesti\^a vys\v{s}ih u\v{c}ebnyh zavedenij. Matematika},
     pages = {26--33},
     publisher = {mathdoc},
     number = {3},
     year = {1982},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/IVM_1982_3_a4/}
}