@article{IVM_1970_5_a14,
     author = {A. Turaev},
     title = {Some criteria for the existence of limit cycles of a~differential equation},
     journal = {Izvesti\^a vys\v{s}ih u\v{c}ebnyh zavedenij. Matematika},
     pages = {92--95},
     publisher = {mathdoc},
     number = {5},
     year = {1970},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/IVM_1970_5_a14/}
}