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@article{DAN_1961_138_4_a6, author = {N. P. Kuptsov}, title = {Conditions for non-selfadjointness of a second-order linear differential operator}, journal = {Doklady Akademii Nauk}, pages = {767--770}, publisher = {mathdoc}, volume = {138}, number = {4}, year = {1961}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/DAN_1961_138_4_a6/} }
N. P. Kuptsov. Conditions for non-selfadjointness of a second-order linear differential operator. Doklady Akademii Nauk, Tome 138 (1961) no. 4, pp. 767-770. http://geodesic.mathdoc.fr/item/DAN_1961_138_4_a6/