@article{MMO_1952_1_a6,
     author = {V. A. Marchenko},
     title = {Some questions of the theory of one-dimensional linear differential operators of the second {order.~I}},
     journal = {Trudy Moskovskogo matemati\v{c}eskogo ob\^{s}estva},
     pages = {327--420},
     publisher = {mathdoc},
     volume = {1},
     year = {1952},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MMO_1952_1_a6/}
}