@article{ZVMMF_1969_9_1_a17,
     author = {G. E. Popov},
     title = {Approximate determination of the limit cycle of van der {Pol's} equation for $\varepsilon\le1$},
     journal = {\v{Z}urnal vy\v{c}islitelʹnoj matematiki i matemati\v{c}eskoj fiziki},
     pages = {207--211},
     publisher = {mathdoc},
     volume = {9},
     number = {1},
     year = {1969},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZVMMF_1969_9_1_a17/}
}