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@article{DE_1979_15_5_a16, author = {Yu. A. Kuznetsov and S. B. Sorokin}, title = {The method of two-sided approximations in eigenvalue problems}, journal = {Differencialʹnye uravneni\^a}, pages = {914--920}, publisher = {mathdoc}, volume = {15}, number = {5}, year = {1979}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/DE_1979_15_5_a16/} }
Yu. A. Kuznetsov; S. B. Sorokin. The method of two-sided approximations in eigenvalue problems. Differencialʹnye uravneniâ, Tome 15 (1979) no. 5, pp. 914-920. http://geodesic.mathdoc.fr/item/DE_1979_15_5_a16/