@inproceedings{bobo2019the,
title={The set of vertices with positive curvature in a planar graph with nonnegative curvature},
author={Bobo Hua, and Yanhui Su},
url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20220318131640735512009},
booktitle={Advances in Mathematics},
volume={343},
pages={789-820},
year={2019},
}

Bobo Hua, and Yanhui Su. The set of vertices with positive curvature in a planar graph with nonnegative curvature. 2019. Vol. 343. In Advances in Mathematics. pp.789-820. http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20220318131640735512009.