@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}, }