@inproceedings{m.1980fredholm,
title={Fredholm pseudo-differential operators on weighted Sobolev spaces},
author={M. W. Wong},
url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203516126145399},
booktitle={Arkiv for Matematik},
volume={21},
number={1},
pages={271-282},
year={1980},
}
M. W. Wong. Fredholm pseudo-differential operators on weighted Sobolev spaces. 1980. Vol. 21. In Arkiv for Matematik. pp.271-282. http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203516126145399.