@article{IVM_1970_5_a7,
     author = {I. S. Kukles and I. G. Rozet},
     title = {Some tests for the absence of limit cycles},
     journal = {Izvesti\^a vys\v{s}ih u\v{c}ebnyh zavedenij. Matematika},
     pages = {53--56},
     publisher = {mathdoc},
     number = {5},
     year = {1970},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/IVM_1970_5_a7/}
}