@article{MMO_1957_6_a1,
     author = {L. A. Skornyakov},
     title = {Systems of curves on a surface},
     journal = {Trudy Moskovskogo matemati\v{c}eskogo ob\^{s}estva},
     pages = {135--164},
     publisher = {mathdoc},
     volume = {6},
     year = {1957},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MMO_1957_6_a1/}
}