@article{GDZPPN002228432,
title = {Counterexamples for unique continuation.},
journal = {Manuscripta mathematica},
volume = {61},
year = {1988},
pages = {21-48},
zbl = {0653.30013},
url = {http://dml.mathdoc.fr/item/GDZPPN002228432}
}
Martio, Olli. Counterexamples for unique continuation.. Manuscripta mathematica, Tome 61 (1988) pp. 21-48. http://gdmltest.u-ga.fr/item/GDZPPN002228432/