@article{AUCMP_1969__10_1-2_a2,
     author = {Koman, M.},
     title = {On the crossing numbers of graphs},
     journal = {Acta Universitatis Carolinae. Mathematica et Physica},
     pages = {9--46},
     publisher = {mathdoc},
     volume = {10},
     number = {1-2},
     year = {1969},
     mrnumber = {0288049},
     zbl = {0256.05103},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/AUCMP_1969__10_1-2_a2/}
}