@article{IVM_1961_6_a9,
     author = {N. V. Medvedev},
     title = {Some problems in the qualitative study of differential equations in the plane},
     journal = {Izvesti\^a vys\v{s}ih u\v{c}ebnyh zavedenij. Matematika},
     pages = {82--88},
     publisher = {mathdoc},
     number = {6},
     year = {1961},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/IVM_1961_6_a9/}
}