@article{1077375074, author = {Nussbaum, A. E.}, title = {Reduction theory for unbounded closed operators in Hilbert space}, journal = {Duke Math. J.}, volume = {31}, number = {1}, year = {1964}, pages = { 33-44}, language = {en}, url = {http://dml.mathdoc.fr/item/1077375074} }
Nussbaum, A. E. Reduction theory for unbounded closed operators in Hilbert space. Duke Math. J., Tome 31 (1964) no. 1, pp. 33-44. http://gdmltest.u-ga.fr/item/1077375074/