@article{1077492271,
author = {Calkin, J. W.},
title = {Symmetric transformations in Hilbert space},
journal = {Duke Math. J.},
volume = {6},
number = {1},
year = {1940},
pages = { 504-508},
language = {en},
url = {http://dml.mathdoc.fr/item/1077492271}
}
Calkin, J. W. Symmetric transformations in Hilbert space. Duke Math. J., Tome 6 (1940) no. 1, pp. 504-508. http://gdmltest.u-ga.fr/item/1077492271/