@inproceedings{alexander2014homotopy,
title={Homotopy Theory for Digraphs},
author={Alexander Grigor’yan, Yong Lin, Yuri Muranov, and Shing-Tung Yau},
url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20180403140954177187008},
booktitle={Pure and Applied Mathematics Quarterly},
volume={10},
pages={619-674},
year={2014},
}
Alexander Grigor’yan, Yong Lin, Yuri Muranov, and Shing-Tung Yau. Homotopy Theory for Digraphs. 2014. Vol. 10. In Pure and Applied Mathematics Quarterly. pp.619-674. http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20180403140954177187008.