@inproceedings{alexandre2009maximization,
title={MAXIMIZATION OF THE SECOND POSITIVE NEUMANN EIGENVALUE FOR PLANAR DOMAINS},
author={Alexandre Girouard, Nikolai Nadirashvili, and Iosif},
url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20160911203709397320808},
booktitle={Journal of Differential Geometry},
volume={83},
number={3},
pages={637-661},
year={2009},
}
Alexandre Girouard, Nikolai Nadirashvili, and Iosif. MAXIMIZATION OF THE SECOND POSITIVE NEUMANN EIGENVALUE FOR PLANAR DOMAINS. 2009. Vol. 83. In Journal of Differential Geometry. pp.637-661. http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20160911203709397320808.