@inproceedings{fengbo2002topology,
title={Topology of sobolev mappings, II},
author={Fengbo Hang, and Fanghua Lin},
url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203342340019638},
booktitle={Acta Mathematica},
volume={191},
number={1},
pages={55-107},
year={2002},
}