@article{GDZPPN002308134,
title = {Non-Uniqueness and Uniqueness in the Cauchy Problem at Simple Characteristic Points.},
journal = {Mathematische Annalen},
volume = {201},
year = {1973},
pages = {231-238},
zbl = {0243.35082},
url = {http://dml.mathdoc.fr/item/GDZPPN002308134}
}
Persson, Jan. Non-Uniqueness and Uniqueness in the Cauchy Problem at Simple Characteristic Points.. Mathematische Annalen, Tome 201 (1973) pp. 231-238. http://gdmltest.u-ga.fr/item/GDZPPN002308134/