@inproceedings{per1989local,
title={Local regularity of solutions to nonlinear Schrödinger equations},
author={Per Sjölin},
url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203532204158532},
booktitle={Arkiv for Matematik},
volume={28},
number={1},
pages={145-157},
year={1989},
}