@article{701329,
title = {A generalization of an Ekeland-Lebourg theorem and the differentiability of distance functions},
booktitle = {Proceedings of the 11th Winter School on Abstract Analysis},
series = {GDML\_Books},
publisher = {Circolo Matematico di Palermo},
address = {Palermo},
year = {1984},
pages = {[403]-410},
mrnumber = {MR0744405},
zbl = {0547.46027},
url = {http://dml.mathdoc.fr/item/701329}
}
Zajíček, L. A generalization of an Ekeland-Lebourg theorem and the differentiability of distance functions, dans Proceedings of the 11th Winter School on Abstract Analysis, GDML_Books, (1984), pp. [403]-410. http://gdmltest.u-ga.fr/item/701329/