@article{GDZPPN002195933,
title = {Existence and regularity of weak solutions to the Dirichletproblem for semilinear elliptic systems of higher order.},
journal = {Journal f\"ur die reine und angewandte Mathematik},
volume = {310},
year = {1979},
pages = {192-207},
zbl = {0395.35026},
url = {http://dml.mathdoc.fr/item/GDZPPN002195933}
}
Luckhaus, Stephan. Existence and regularity of weak solutions to the Dirichletproblem for semilinear elliptic systems of higher order.. Journal für die reine und angewandte Mathematik, Tome 310 (1979) pp. 192-207. http://gdmltest.u-ga.fr/item/GDZPPN002195933/