@inproceedings{p.1978a,
title={A generalisation of Widman's theorem on comparison domains for harmonic measures},
author={P. J. Rippon},
url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203504824161304},
booktitle={Arkiv for Matematik},
volume={17},
number={1},
pages={39-50},
year={1978},
}
P. J. Rippon. A generalisation of Widman's theorem on comparison domains for harmonic measures. 1978. Vol. 17. In Arkiv for Matematik. pp.39-50. http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203504824161304.