@article{GDZPPN00202442X,
title = {Bounds for the Second Eigenvalue of a Positive Operator. (Short Communication).},
journal = {Aequationes mathematicae},
volume = {5},
year = {1970},
pages = {397-397},
url = {http://dml.mathdoc.fr/item/GDZPPN00202442X}
}
Hadeler, K.P. Bounds for the Second Eigenvalue of a Positive Operator. (Short Communication).. Aequationes mathematicae, Tome 5 (1970) p. 397. http://gdmltest.u-ga.fr/item/GDZPPN00202442X/