@article{IVM_1990_12_a7,
     author = {N. G. Makeev},
     title = {A~differential equation that determines the {Poincar\'e} function in a~neighborhood of a~focus},
     journal = {Izvesti\^a vys\v{s}ih u\v{c}ebnyh zavedenij. Matematika},
     pages = {55--62},
     publisher = {mathdoc},
     number = {12},
     year = {1990},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/IVM_1990_12_a7/}
}