@article{GDZPPN002399822,
title = {Symmetrie elliptischer Differentialoperatoren.},
journal = {Mathematische Zeitschrift},
volume = {99},
year = {1967},
pages = {401-406},
zbl = {0146.34302},
url = {http://dml.mathdoc.fr/item/GDZPPN002399822}
}
Walter, Johann. Symmetrie elliptischer Differentialoperatoren.. Mathematische Zeitschrift, Tome 99 (1967) pp. 401-406. http://gdmltest.u-ga.fr/item/GDZPPN002399822/