@inproceedings{erik1955some,
title={Some groups of order$p$^{$r$}$q$^{$s$}with abelian subgroups of order$p$^{$r$}contained in the central},
author={Erik Götlind},
url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203419092682911},
booktitle={Arkiv for Matematik},
volume={3},
number={2},
pages={165-169},
year={1955},
}
Erik Götlind. Some groups of order$p$^{$r$}$q$^{$s$}with abelian subgroups of order$p$^{$r$}contained in the central. 1955. Vol. 3. In Arkiv for Matematik. pp.165-169. http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203419092682911.