@article{DE_1968_4_2_a1,
     author = {Yu. F. Shain},
     title = {Investigation of the motions of a spherical pendulum in the presence of a switching rotating force},
     journal = {Differencialʹnye uravneni\^a},
     pages = {215--224},
     year = {1968},
     volume = {4},
     number = {2},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1968_4_2_a1/}
}