@article{MZ_1993__213_1_174547,
     author = {Robert Hardt and Fang Hua Lin},
     title = {Harmonic maps into round cones and singularities of nematic liquid crystals.},
     journal = {Mathematische Zeitschrift},
     pages = {575--594},
     publisher = {mathdoc},
     volume = {213},
     number = {1},
     year = {1993},
     zbl = {0790.58010},
     url = {http://geodesic.mathdoc.fr/item/MZ_1993__213_1_174547/}
}