@inproceedings{gueo2000geometry,
title={Geometry of hyper-Khler connections with torsion},
author={Gueo Grantcharov, and Yat Sun Poon},
url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20191020220133030220320},
booktitle={Communications in Mathematical Physics},
volume={213},
number={1},
pages={19-37},
year={2000},
}

Gueo Grantcharov, and Yat Sun Poon. Geometry of hyper-Khler connections with torsion. 2000. Vol. 213. In Communications in Mathematical Physics. pp.19-37. http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20191020220133030220320.