@article{DE_1973_9_2_a23,
     author = {I. V. Kamenev},
     title = {Oscillation critieria for a linear second order equation that are connected with the existence of a ``principal'' solution},
     journal = {Differencialʹnye uravneni\^a},
     pages = {370--373},
     publisher = {mathdoc},
     volume = {9},
     number = {2},
     year = {1973},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1973_9_2_a23/}
}