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@article{DAN_1970_193_6_a8, author = {P. E. Sobolevskii}, title = {On $S$-numbers of positive operators}, journal = {Doklady Akademii Nauk}, pages = {1245--1247}, publisher = {mathdoc}, volume = {193}, number = {6}, year = {1970}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/DAN_1970_193_6_a8/} }
P. E. Sobolevskii. On $S$-numbers of positive operators. Doklady Akademii Nauk, Tome 193 (1970) no. 6, pp. 1245-1247. http://geodesic.mathdoc.fr/item/DAN_1970_193_6_a8/