@article{DE_1989_25_4_a21,
     author = {B. S. Kalitin},
     title = {On a problem of {Florio} and {Seibert}},
     journal = {Differencialʹnye uravneni\^a},
     pages = {727--729},
     publisher = {mathdoc},
     volume = {25},
     number = {4},
     year = {1989},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1989_25_4_a21/}
}