@article{DE_1976_12_2_a21,
     author = {V. S. Mokeichev},
     title = {Eigenvalues of a periodic boundary value problem for certain partial differential equations},
     journal = {Differencialʹnye uravneni\^a},
     pages = {356--358},
     publisher = {mathdoc},
     volume = {12},
     number = {2},
     year = {1976},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1976_12_2_a21/}
}