@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 {\textquotedblleft}principal{\textquotedblright} solution}, journal = {Differencialʹnye uravneni\^a}, pages = {370--373}, year = {1973}, volume = {9}, number = {2}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/DE_1973_9_2_a23/} }