@inproceedings{james2004existence,
title={Existence of KPP type fronts in space-time periodic shear flows and a study of minimal speeds based on variational principle},
author={James Nolen, and Jack Xin},
url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20191224210137749081407},
booktitle={arXiv preprint math/0407366},
year={2004},
}
James Nolen, and Jack Xin. Existence of KPP type fronts in space-time periodic shear flows and a study of minimal speeds based on variational principle. 2004. In arXiv preprint math/0407366. http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20191224210137749081407.