@inproceedings{albert1982the,
title={The Heights theorem for quadratic differentials on Riemann surfaces},
author={Albert Marden, and Kurt Strebel},
url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203302802323359},
booktitle={Acta Mathematica},
volume={153},
number={1},
pages={153-211},
year={1982},
}
Albert Marden, and Kurt Strebel. The Heights theorem for quadratic differentials on Riemann surfaces. 1982. Vol. 153. In Acta Mathematica. pp.153-211. http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203302802323359.