@article{DE_1995_31_7_a20,
     author = {L. F. Yukhno},
     title = {Generalization of the {Wittrick{\textendash}Williams} method to nonlinear spectral problems with a multiple spectrum},
     journal = {Differencialʹnye uravneni\^a},
     pages = {1261--1264},
     year = {1995},
     volume = {31},
     number = {7},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1995_31_7_a20/}
}