@article{GDZPPN002061015,
title = {Integrability in Codimension 1},
journal = {Commentarii mathematici Helvetici},
volume = {48},
year = {1973},
pages = {195-233},
zbl = {0284.57016},
url = {http://dml.mathdoc.fr/item/GDZPPN002061015}
}
Mather, John N. Integrability in Codimension 1. Commentarii mathematici Helvetici, Tome 48 (1973) pp. 195-233. http://gdmltest.u-ga.fr/item/GDZPPN002061015/