@article{GDZPPN002204096,
title = {Bases in solution sheaves of systems of partial differential equations.},
journal = {Journal f\"ur die reine und angewandte Mathematik},
volume = {374},
year = {1987},
pages = {1-36},
zbl = {0595.35021},
url = {http://dml.mathdoc.fr/item/GDZPPN002204096}
}
Langenbruch, Michael. Bases in solution sheaves of systems of partial differential equations.. Journal für die reine und angewandte Mathematik, Tome 374 (1987) pp. 1-36. http://gdmltest.u-ga.fr/item/GDZPPN002204096/