@article{SEMR_2005_2_a17,
     author = {O. V. Borodin and A. O. Ivanova},
     title = {An oriented colouring of planar graphs with girth at least~$4$},
     journal = {Sibirskie \`elektronnye matemati\v{c}eskie izvesti\^a},
     pages = {239--249},
     publisher = {mathdoc},
     volume = {2},
     year = {2005},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/SEMR_2005_2_a17/}
}