@article{GDZPPN002310007,
title = {On the Approximation Numbers of an Operator and Its Adjoint.},
journal = {Mathematische Annalen},
volume = {212},
year = {1974},
pages = {277-280},
zbl = {0272.47017},
url = {http://dml.mathdoc.fr/item/GDZPPN002310007}
}
Hutton, C.V. On the Approximation Numbers of an Operator and Its Adjoint.. Mathematische Annalen, Tome 212 (1974) pp. 277-280. http://gdmltest.u-ga.fr/item/GDZPPN002310007/