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@article{DAN_1962_145_3_a8, author = {I. S. Kats}, title = {On the spectral multiplicity of a second-order differential operator}, journal = {Doklady Akademii Nauk}, pages = {510--513}, publisher = {mathdoc}, volume = {145}, number = {3}, year = {1962}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/DAN_1962_145_3_a8/} }
I. S. Kats. On the spectral multiplicity of a second-order differential operator. Doklady Akademii Nauk, Tome 145 (1962) no. 3, pp. 510-513. http://geodesic.mathdoc.fr/item/DAN_1962_145_3_a8/