@article{DE_1978_14_4_a25,
     author = {O. M. Yudrups},
     title = {Continual equivalence of dynamical systems on the sphere},
     journal = {Differencialʹnye uravneni\^a},
     pages = {753--754},
     publisher = {mathdoc},
     volume = {14},
     number = {4},
     year = {1978},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1978_14_4_a25/}
}