@inproceedings{göran1981convexity,
title={Convexity of means and growth of certain subharmonic functions in an$n$-dimensional cone},
author={Göran Wanby},
url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203514251591383},
booktitle={Arkiv for Matematik},
volume={21},
number={1},
pages={29-43},
year={1981},
}
Göran Wanby. Convexity of means and growth of certain subharmonic functions in an$n$-dimensional cone. 1981. Vol. 21. In Arkiv for Matematik. pp.29-43. http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203514251591383.