@inproceedings{sigbert1968the,
title={The subset of piecewise-linear mappings is dense in the space of$K$-quasiconformal mappings of the plane},
author={Sigbert Jaenisch},
url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203217107980074},
booktitle={Acta Mathematica},
volume={122},
number={1},
pages={265-272},
year={1968},
}
Sigbert Jaenisch. The subset of piecewise-linear mappings is dense in the space of$K$-quasiconformal mappings of the plane. 1968. Vol. 122. In Acta Mathematica. pp.265-272. http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203217107980074.