@article{DAN_1976_231_1_a2,
     author = {O. V. Borodin},
     title = {A proof of {Gr\"unbaum's} conjecture on the acyclic $5$-colorability of planar graphs},
     journal = {Doklady Akademii Nauk},
     pages = {18--20},
     publisher = {mathdoc},
     volume = {231},
     number = {1},
     year = {1976},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1976_231_1_a2/}
}