@article{DAN_1958_119_4_a8,
     author = {Chan Chi-fen},
     title = {On the uniqueness of the limit cycles of some non-linear oscillation equations},
     journal = {Doklady Akademii Nauk},
     pages = {659--662},
     publisher = {mathdoc},
     volume = {119},
     number = {4},
     year = {1958},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1958_119_4_a8/}
}