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@article{TM_1990_192_a5, author = {Yu. V. Egorov and V. A. Kondrat'ev}, title = {On the negative spectrum of an elliptic operator}, journal = {Trudy Matematicheskogo Instituta imeni V.A. Steklova}, pages = {61--67}, publisher = {mathdoc}, volume = {192}, year = {1990}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/TM_1990_192_a5/} }
Yu. V. Egorov; V. A. Kondrat'ev. On the negative spectrum of an elliptic operator. Trudy Matematicheskogo Instituta imeni V.A. Steklova, Differential equations and functional spaces, Tome 192 (1990), pp. 61-67. http://geodesic.mathdoc.fr/item/TM_1990_192_a5/