@article{MZ_1971__121_171569,
     author = {Jens Frehse},
     title = {A {Regularity} {Result} for {Nonlinear} {Elliptic} {Systems.}},
     journal = {Mathematische Zeitschrift},
     pages = {305--310},
     publisher = {mathdoc},
     volume = {121},
     year = {1971},
     zbl = {0219.35036},
     url = {http://geodesic.mathdoc.fr/item/MZ_1971__121_171569/}
}