@inproceedings{fang2002weak,
title={Weak Hopf Algebras and Singular Solutions of Quantum Yang–Baxter Equation},
author={Fang Li, and Steven Duplij},
url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170209100548424452370},
booktitle={Communications in Mathematical Physcis},
volume={225},
pages={27},
year={2002},
}

Fang Li, and Steven Duplij. Weak Hopf Algebras and Singular Solutions of Quantum Yang–Baxter Equation. 2002. Vol. 225. In Communications in Mathematical Physcis. pp.27. http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170209100548424452370.