@article{DE_1995_31_4_a0,
     author = {N. N. Butenina and Z. G. Pavlyuchonok and V. P. Savel'ev},
     title = {Qualitative methods for the global investigation of controllability regions on a plane},
     journal = {Differencialʹnye uravneni\^a},
     pages = {555--568},
     publisher = {mathdoc},
     volume = {31},
     number = {4},
     year = {1995},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1995_31_4_a0/}
}