@article{GDZPPN002104474,
title = {The ?-constant stratum is not smooth.},
journal = {Inventiones mathematicae},
volume = {88},
year = {1987},
pages = {139-152},
zbl = {0627.32018},
url = {http://dml.mathdoc.fr/item/GDZPPN002104474}
}
Luengo, L. The ?-constant stratum is not smooth.. Inventiones mathematicae, Tome 88 (1987) pp. 139-152. http://gdmltest.u-ga.fr/item/GDZPPN002104474/