@inproceedings{sadahiro1972on,
title={On strong Ditkin sets},
author={Sadahiro Saeki},
url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203448159003160},
booktitle={Arkiv for Matematik},
volume={10},
number={1},
pages={1-7},
year={1972},
}