@inproceedings{s.1979minimal, title={Minimal surfaces with free boundaries}, author={S. Hildebrandt, and J. C. C. Nitsche}, url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203250612364268}, booktitle={Acta Mathematica}, volume={143}, number={1}, pages={251-272}, year={1979}, }