@article{MZ_1970__118_171462,
     author = {Willi J\"ager and Stefan Hildebrandt},
     title = {On the {Regularity} of {Surfaces} with {Prescribed} {Mean} {Curvature} at a {Free} {Boundary.}},
     journal = {Mathematische Zeitschrift},
     pages = {289--308},
     year = {1970},
     volume = {118},
     zbl = {0204.11504},
     url = {http://geodesic.mathdoc.fr/item/MZ_1970__118_171462/}
}