@article{GDZPPN00209844X,
title = {An Eigenvalue Pinching Theorem.},
journal = {Inventiones mathematicae},
volume = {69},
year = {1982},
pages = {253-256},
zbl = {0505.53018},
url = {http://dml.mathdoc.fr/item/GDZPPN00209844X}
}
Croke, Christopher B. An Eigenvalue Pinching Theorem.. Inventiones mathematicae, Tome 69 (1982) pp. 253-256. http://gdmltest.u-ga.fr/item/GDZPPN00209844X/