@inproceedings{l.1885über,
title={Über $$\int\limits_0^\infty {\frac{{\sin ax}}{{\sin bx}}} \frac{{dx}}{{1 + x^2 }}$$ und Verwandte Integrale},
author={L. Schläfli},
url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108202938166529820},
booktitle={Acta Mathematica},
volume={7},
number={1},
pages={187-196},
year={1885},
}
L. Schläfli. Über $$\int\limits_0^\infty {\frac{{\sin ax}}{{\sin bx}}} \frac{{dx}}{{1 + x^2 }}$$ und Verwandte Integrale. 1885. Vol. 7. In Acta Mathematica. pp.187-196. http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108202938166529820.