@inproceedings{pavel2002quantum,
title={Quantum mechanics of layers with a finite number of point perturbations},
author={Pavel Exner, and K Nmcov},
url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20191020125829234093627},
booktitle={Journal of Mathematical Physics},
volume={43},
number={3},
pages={1152-1184},
year={2002},
}

Pavel Exner, and K Nmcov. Quantum mechanics of layers with a finite number of point perturbations. 2002. Vol. 43. In Journal of Mathematical Physics. pp.1152-1184. http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20191020125829234093627.