@article{GDZPPN002231360,
title = {A lower bound for the least eigenvalue of ... + V.},
journal = {Manuscripta mathematica},
volume = {67},
year = {1990},
pages = {255-260},
zbl = {0717.58056},
url = {http://dml.mathdoc.fr/item/GDZPPN002231360}
}
Bérard, Pierre. A lower bound for the least eigenvalue of ... + V.. Manuscripta mathematica, Tome 67 (1990) pp. 255-260. http://gdmltest.u-ga.fr/item/GDZPPN002231360/