@inproceedings{j.1953a,
title={A non-harmonic fourier series},
author={J. M. Hammersley},
url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203137679711779},
booktitle={Acta Mathematica},
volume={89},
number={1},
pages={243-260},
year={1953},
}