@article{01930020, title = {Riesz bases and positive operators on Hilbert space.}, journal = {International Journal of Mathematics and Mathematical Sciences}, volume = {2003}, year = {2003}, pages = {1173-1174}, doi = {10.1155/S0161171203202349}, zbl = {1027.46023}, language = {en}, url = {http://dml.mathdoc.fr/item/01930020} }
Holub, James R. Riesz bases and positive operators on Hilbert space.. International Journal of Mathematics and Mathematical Sciences, Tome 2003 (2003) pp. 1173-1174. doi : 10.1155/S0161171203202349. http://gdmltest.u-ga.fr/item/01930020/