@article{DAN_1991_321_4_a8,
     author = {L. G. Mikhailov},
     title = {A property of singular differential equations},
     journal = {Doklady Akademii Nauk},
     pages = {681--686},
     publisher = {mathdoc},
     volume = {321},
     number = {4},
     year = {1991},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1991_321_4_a8/}
}