@article{SJIM_2018_21_1_a4,
     author = {A. A. Kosov and E. I. Semenov},
     title = {First integrals and periodic solutions of a~system with power nonlinearities},
     journal = {Sibirskij \v{z}urnal industrialʹnoj matematiki},
     pages = {47--60},
     publisher = {mathdoc},
     volume = {21},
     number = {1},
     year = {2018},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/SJIM_2018_21_1_a4/}
}