@inproceedings{juha1996quasiconformal,
title={Quasiconformal maps in metric spaces with controlled geometry},
author={Juha Heinonen, and Pekka Koskela},
url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203331412763564},
booktitle={Acta Mathematica},
volume={181},
number={1},
pages={1-61},
year={1996},
}
Juha Heinonen, and Pekka Koskela. Quasiconformal maps in metric spaces with controlled geometry. 1996. Vol. 181. In Acta Mathematica. pp.1-61. http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203331412763564.