@inproceedings{makoto1990regularity, title={Regularity of a boundary having a Schwarz function}, author={Makoto Sakai}, url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203316343358457}, booktitle={Acta Mathematica}, volume={166}, number={1}, pages={263-297}, year={1990}, }