@inproceedings{walter2005proof,
title={Proof of a conjecture of Pólya on the zeros of successive derivatives of real entire functions},
author={Walter Bergweiler, and Alexandre Eremenko},
url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203349823184686},
booktitle={Acta Mathematica},
volume={197},
number={2},
pages={145-166},
year={2005},
}

Walter Bergweiler, and Alexandre Eremenko. Proof of a conjecture of Pólya on the zeros of successive derivatives of real entire functions. 2005. Vol. 197. In Acta Mathematica. pp.145-166. http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203349823184686.