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@article{DAN_1963_150_4_a4, author = {M. M. Gekhtman}, title = {On the spectrum of a non-selfadjoint differential operator of even order}, journal = {Doklady Akademii Nauk}, pages = {726--729}, publisher = {mathdoc}, volume = {150}, number = {4}, year = {1963}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/DAN_1963_150_4_a4/} }
M. M. Gekhtman. On the spectrum of a non-selfadjoint differential operator of even order. Doklady Akademii Nauk, Tome 150 (1963) no. 4, pp. 726-729. http://geodesic.mathdoc.fr/item/DAN_1963_150_4_a4/