@inproceedings{kefeng2017formal,
title={Formal pseudodifferential operators and Witten's r-spin numbers},
author={Kefeng Liu, Ravi Vakil, and Hao Xu},
url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20191221111516419641655},
booktitle={arXiv preprint arXiv:1112.4601},
year={2017},
}
Kefeng Liu, Ravi Vakil, and Hao Xu. Formal pseudodifferential operators and Witten's r-spin numbers. 2017. In arXiv preprint arXiv:1112.4601. http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20191221111516419641655.