@inproceedings{fancoverings,,
title={Coverings, heat kernels and spanning trees},
author={Fan Chung, and Shing-Tung Yau},
url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20191224203720220609074},
booktitle={Journal of Combinatorics},
volume={6},
pages={163-184},
}