@article{DE_1996_32_4_a5,
     author = {Yu. N. Kiselev},
     title = {Control systems with an integral invariant},
     journal = {Differencialʹnye uravneni\^a},
     pages = {477--483},
     publisher = {mathdoc},
     volume = {32},
     number = {4},
     year = {1996},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1996_32_4_a5/}
}