@article{GDZPPN002197375,
title = {On the regularity of weak solutions to non linear elliptic systems of partial differential equations.},
journal = {Journal f\"ur die reine und angewandte Mathematik},
volume = {316},
year = {1980},
pages = {140-159},
zbl = {0435.35036},
url = {http://dml.mathdoc.fr/item/GDZPPN002197375}
}
Giaquinta, M.; Necas, J. On the regularity of weak solutions to non linear elliptic systems of partial differential equations.. Journal für die reine und angewandte Mathematik, Tome 316 (1980) pp. 140-159. http://gdmltest.u-ga.fr/item/GDZPPN002197375/