@article{MM2_1980__33_154754,
     author = {S. Hildebrandt and J.C.C. Nitsche},
     title = {Optimal {Boundary} {Regularity} for {Minimal} {Surfaces} with a {Free} {Boundary.}},
     journal = {Manuscripta mathematica},
     pages = {357--364},
     publisher = {mathdoc},
     volume = {33},
     year = {1980},
     zbl = {0465.49029},
     url = {http://geodesic.mathdoc.fr/item/MM2_1980__33_154754/}
}