@article{MZM_1998_64_5_a8,
     author = {A. A. Panov},
     title = {The number of periodic solutions of polynomial differential equations},
     journal = {Matemati\v{c}eskie zametki},
     pages = {720--727},
     year = {1998},
     volume = {64},
     number = {5},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1998_64_5_a8/}
}