@inproceedings{pavel2016optimization,
title={Optimization of the lowest eigenvalue for leaky star graphs},
author={Pavel Exner, and Vladimir Lotoreichik},
url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20191020133947502762757},
booktitle={Proceedings of the conference Mathematical Results in Quantum Physics(QMath13, Atlanta 2016},
pages={187-196},
year={2016},
}

Pavel Exner, and Vladimir Lotoreichik. Optimization of the lowest eigenvalue for leaky star graphs. 2016. In Proceedings of the conference Mathematical Results in Quantum Physics(QMath13, Atlanta 2016. pp.187-196. http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20191020133947502762757.