@inproceedings{leonid2003comparison,
title={Comparison theorems for the one-dimensional Schrödinger equation},
author={Leonid V. Kovalev},
url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203615300636874},
booktitle={Arkiv for Matematik},
volume={43},
number={2},
pages={403-418},
year={2003},
}
Leonid V. Kovalev. Comparison theorems for the one-dimensional Schrödinger equation. 2003. Vol. 43. In Arkiv for Matematik. pp.403-418. http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203615300636874.