@article{DAN_1963_149_2_a14,
     author = {V. N. Chevelo and V. G. Shtelik},
     title = {Some problems in the oscillation of solutions of nonlinear, non-autonomous second-order equations},
     journal = {Doklady Akademii Nauk},
     pages = {276--279},
     publisher = {mathdoc},
     volume = {149},
     number = {2},
     year = {1963},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1963_149_2_a14/}
}