@article{1077466680,
author = {Hartman, Philip and Putnam, Calvin R.},
title = {The essential spectrum and averages of the potential},
journal = {Duke Math. J.},
volume = {23},
number = {1},
year = {1956},
pages = { 83-91},
language = {en},
url = {http://dml.mathdoc.fr/item/1077466680}
}
Hartman, Philip; Putnam, Calvin R. The essential spectrum and averages of the potential. Duke Math. J., Tome 23 (1956) no. 1, pp. 83-91. http://gdmltest.u-ga.fr/item/1077466680/