@article{DAN_1991_316_2_a1,
     author = {K. Yu. Gorbunov},
     title = {Context-free deducibility of graphs that do not realize a planar},
     journal = {Doklady Akademii Nauk},
     pages = {270--274},
     publisher = {mathdoc},
     volume = {316},
     number = {2},
     year = {1991},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1991_316_2_a1/}
}