@inproceedings{lars1964non-associative,
title={Non-associative normed algebras and hurwitz' problem},
author={Lars Ingelstam},
url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203431027802015},
booktitle={Arkiv for Matematik},
volume={5},
number={3},
pages={231-238},
year={1964},
}