@article{GDZPPN002212048,
title = {Geometry and topology of the boundary in the critical Neumann problem.},
journal = {Journal f\"ur die reine und angewandte Mathematik},
volume = {450},
year = {1994},
pages = {1-18},
zbl = {0804.35036},
url = {http://dml.mathdoc.fr/item/GDZPPN002212048}
}
Mancini, G.; Adimurthi. Geometry and topology of the boundary in the critical Neumann problem.. Journal für die reine und angewandte Mathematik, Tome 450 (1994) pp. 1-18. http://gdmltest.u-ga.fr/item/GDZPPN002212048/