@inproceedings{henry1953isomorphisms,
title={Isomorphisms of abelian group algebras},
author={Henry Helson},
url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203417393992896},
booktitle={Arkiv for Matematik},
volume={2},
number={5},
pages={475-487},
year={1953},
}