@article{01151682, title = {The gradient method for non-differentiable operators in product Hilbert spaces and applications to elliptic systems of quasilinear differential equations.}, journal = {Journal of Applied Analysis}, volume = {3}, year = {1997}, pages = {225-237}, doi = {10.1515/JAA.1997.225}, zbl = {0899.46061}, language = {en}, url = {http://dml.mathdoc.fr/item/01151682} }
Karátson, J. The gradient method for non-differentiable operators in product Hilbert spaces and applications to elliptic systems of quasilinear differential equations.. Journal of Applied Analysis, Tome 3 (1997) pp. 225-237. doi : 10.1515/JAA.1997.225. http://gdmltest.u-ga.fr/item/01151682/