@inproceedings{göran1949on,
title={On the completeness of some sets of functions},
author={Göran Borg},
url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203125916373691},
booktitle={Acta Mathematica},
volume={81},
number={1},
pages={265-283},
year={1949},
}