@inproceedings{mikhail1993discrete,
title={Discrete spectrum of the perturbed Dirac operator},
author={Mikhail Sh. Birman, and Ari Laptev},
url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203541852890613},
booktitle={Arkiv for Matematik},
volume={32},
number={1},
pages={13-32},
year={1993},
}
Mikhail Sh. Birman, and Ari Laptev. Discrete spectrum of the perturbed Dirac operator. 1993. Vol. 32. In Arkiv for Matematik. pp.13-32. http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203541852890613.