@article{GDZPPN002311275,
title = {Stability of Caustics.},
journal = {Mathematische Annalen},
volume = {217},
year = {1975},
pages = {43-50},
zbl = {0293.58008},
url = {http://dml.mathdoc.fr/item/GDZPPN002311275}
}
Wassermann, Gordon. Stability of Caustics.. Mathematische Annalen, Tome 217 (1975) pp. 43-50. http://gdmltest.u-ga.fr/item/GDZPPN002311275/