@inproceedings{bjorn2018approximate,
title={Approximate Separability of the Green's Function of the Helmholtz Equation in the High Frequency Limit},
author={Bjorn Engquist, and Hongkai Zhao},
url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20180219045301772484932},
booktitle={Communications on Pure and Applied Mathematics},
year={2018},
}
Bjorn Engquist, and Hongkai Zhao. Approximate Separability of the Green's Function of the Helmholtz Equation in the High Frequency Limit. 2018. In Communications on Pure and Applied Mathematics. http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20180219045301772484932.