@article{DE_1973_9_9_a22,
     author = {G. L. Yuzbashev},
     title = {A study of the set of periodic solutions of a certain system of second order differential equations without dissipation},
     journal = {Differencialʹnye uravneni\^a},
     pages = {1734--1737},
     publisher = {mathdoc},
     volume = {9},
     number = {9},
     year = {1973},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1973_9_9_a22/}
}