@article{GDZPPN002223422,
title = {Stability Theorems for Singular Perturbation of Eigenvalues.},
journal = {Manuscripta mathematica},
volume = {35},
year = {1981},
pages = {157-174},
zbl = {0489.47004},
url = {http://dml.mathdoc.fr/item/GDZPPN002223422}
}
Greenlee, W.M. Stability Theorems for Singular Perturbation of Eigenvalues.. Manuscripta mathematica, Tome 35 (1981) pp. 157-174. http://gdmltest.u-ga.fr/item/GDZPPN002223422/