@article{DAN_1958_118_1_a1,
     author = {V. G. Boltyanskii},
     title = {Homotopical classification of vector fields},
     journal = {Doklady Akademii Nauk},
     pages = {13--16},
     publisher = {mathdoc},
     volume = {118},
     number = {1},
     year = {1958},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1958_118_1_a1/}
}