@article{DAN_1963_153_1_a1,
     author = {Yu. G. Borisovich},
     title = {An application of the concept of rotation of a vector field},
     journal = {Doklady Akademii Nauk},
     pages = {12--15},
     publisher = {mathdoc},
     volume = {153},
     number = {1},
     year = {1963},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1963_153_1_a1/}
}