@inproceedings{jean-pierre1994upper,
title={Upper bound for the first eigenvalue of algebraic submanifolds},
author={Jean-Pierre Bourguignon, Peter Li, and Shing-Tung Yau},
url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20191224203747851434081},
booktitle={Commentarii Mathematici Helvetici},
volume={69},
number={2},
pages={199-207},
year={1994},
}

Jean-Pierre Bourguignon, Peter Li, and Shing-Tung Yau. Upper bound for the first eigenvalue of algebraic submanifolds. 1994. Vol. 69. In Commentarii Mathematici Helvetici. pp.199-207. http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20191224203747851434081.