@inproceedings{a.1931almost,
title={Almost periodicity and general trigonometric series},
author={A. S. Besicovitch, and H. Bohr},
url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203057958861478},
booktitle={Acta Mathematica},
volume={57},
number={1},
pages={203-292},
year={1931},
}
A. S. Besicovitch, and H. Bohr. Almost periodicity and general trigonometric series. 1931. Vol. 57. In Acta Mathematica. pp.203-292. http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203057958861478.