@article{DAN_1975_222_6_a5,
     author = {V. A. Marchenko and I. V. Ostrovskii},
     title = {A characterization of the spectrum of {Hill{\textquoteright}s} operator},
     journal = {Doklady Akademii Nauk},
     pages = {1283--1286},
     publisher = {mathdoc},
     volume = {222},
     number = {6},
     year = {1975},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1975_222_6_a5/}
}