@article{DAN_1975_222_6_a13,
     author = {R. A. Smolkin},
     title = {A graph transformation problem},
     journal = {Doklady Akademii Nauk},
     pages = {1311--1314},
     publisher = {mathdoc},
     volume = {222},
     number = {6},
     year = {1975},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1975_222_6_a13/}
}