@article{DE_1976_12_4_a18,
     author = {I. V. Kamenev},
     title = {Necessary and sufficient conditions for the disconjugacy of the solutions of a second order linear equation},
     journal = {Differencialʹnye uravneni\^a},
     pages = {751--753},
     publisher = {mathdoc},
     volume = {12},
     number = {4},
     year = {1976},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1976_12_4_a18/}
}