@inproceedings{weierstrass1923briefe, title={Briefe von K. Weierstrass an L. Fuchs.}, author={Weierstrass}, url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203038287028325}, booktitle={Acta Mathematica}, volume={39}, number={1}, pages={246-256}, year={1923}, }