@article{DE_1975_11_6_a18,
     author = {I. V. Kamenev},
     title = {On {Hartman's} comparison theorem for second order linear equations},
     journal = {Differencialʹnye uravneni\^a},
     pages = {1136--1137},
     publisher = {mathdoc},
     volume = {11},
     number = {6},
     year = {1975},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1975_11_6_a18/}
}