@inproceedings{pavel2004spectra,
title={Spectra of soft ring graphs},
author={Pavel Exner, and M Tater},
url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20191020130617118357650},
booktitle={Waves in Random Media},
volume={14},
number={1},
pages={S47-60},
year={2004},
}