@inproceedings{l.1957note,
title={Note on a Lemma of Finn and Gilbarg},
author={L. E. Payne, and H. F. Weinberger},
url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203148439869859},
booktitle={Acta Mathematica},
volume={98},
number={1},
pages={297-299},
year={1957},
}