@inproceedings{qiang2012analysis,
title={Analysis and Approximation of Nonlocal Diffusion Problems with Volume Constraints},
author={Qiang Du, Max Gunzburger, Rich Lehoucq, and Kun Zhou},
url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170314195210680155703},
booktitle={SIAM Review},
volume={54},
number={4},
pages={667-696},
year={2012},
}

Qiang Du, Max Gunzburger, Rich Lehoucq, and Kun Zhou. Analysis and Approximation of Nonlocal Diffusion Problems with Volume Constraints. 2012. Vol. 54. In SIAM Review. pp.667-696. http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170314195210680155703.