@article{DAN_1964_158_6_a5,
     author = {M. H. Zakhar-Itkin},
     title = {Investigation of a differential equation of {Sturm{\textendash}Liouville} type},
     journal = {Doklady Akademii Nauk},
     pages = {1264--1267},
     year = {1964},
     volume = {158},
     number = {6},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1964_158_6_a5/}
}