@inproceedings{hans1941beweis, title={Beweis einer Caratheodoryschen Vermutung}, author={Hans Ludwig Hamburger}, url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203116948635625}, booktitle={Acta Mathematica}, volume={73}, number={1}, pages={175-332}, year={1941}, }