Voir la notice de l'article provenant de la source Hellenic Digital Mathematics Library
@article{EUG_1987__14_a2, author = {I. Istratescu}, title = {On some classes of {Operators} on {Hilbert} spaces}, journal = {E\ensuremath{\upsilon}\ensuremath{\kappa}\ensuremath{\lambda}\ensuremath{\varepsilon}\ensuremath{\acute\iota}\ensuremath{\delta}\ensuremath{\eta}\ensuremath{\varsigma} \ensuremath{\Gamma} }, pages = {15-18}, publisher = {mathdoc}, volume = {14}, year = {1987}, language = {gr}, url = {http://geodesic.mathdoc.fr/item/EUG_1987__14_a2/} }
I. Istratescu. On some classes of Operators on Hilbert spaces. Ευκλείδης Γ , Tome 14 (1987), p. 15-18. http://geodesic.mathdoc.fr/item/EUG_1987__14_a2/