@article{DAN_1973_209_5_a13,
     author = {P. E. Krasnushkin},
     title = {The properties of normal waves in periodic wave guides close to the multiplicity of the wave numbers},
     journal = {Doklady Akademii Nauk},
     pages = {1053--1056},
     publisher = {mathdoc},
     volume = {209},
     number = {5},
     year = {1973},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1973_209_5_a13/}
}