@inproceedings{j.1962random,
title={Random walks with spherical symmetry},
author={J. F. C. Kingman},
url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203200354709948},
booktitle={Acta Mathematica},
volume={109},
number={1},
pages={11-53},
year={1962},
}