@article{GDZPPN002416107,
title = {Eigenvalue Comparison Theorems and Its Geometric Applications.},
journal = {Mathematische Zeitschrift},
volume = {142},
year = {1975},
pages = {289-297},
zbl = {0329.53035},
url = {http://dml.mathdoc.fr/item/GDZPPN002416107}
}
Cheng, Shiu-Yuen. Eigenvalue Comparison Theorems and Its Geometric Applications.. Mathematische Zeitschrift, Tome 142 (1975) pp. 289-297. http://gdmltest.u-ga.fr/item/GDZPPN002416107/