@article{JRAM_1983__343_152552,
     author = {Willi J\"ager and Helmut Kaul},
     title = {Rotationally symmetric harmonic maps from a ball into a sphere and the regularity problem for weak solutions of elliptic systems.},
     journal = {Journal f\"ur die reine und angewandte Mathematik},
     pages = {146--161},
     publisher = {mathdoc},
     volume = {343},
     year = {1983},
     zbl = {0516.35032},
     url = {http://geodesic.mathdoc.fr/item/JRAM_1983__343_152552/}
}