@inproceedings{henry1959the,
title={The functions which operate on Fourier transforms},
author={Henry Helson, Jean-Pierre Kahane, Yitzhak Katznelson, and Walter Rudin},
url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203152975702892},
booktitle={Acta Mathematica},
volume={102},
number={1},
pages={135-157},
year={1959},
}
Henry Helson, Jean-Pierre Kahane, Yitzhak Katznelson, and Walter Rudin. The functions which operate on Fourier transforms. 1959. Vol. 102. In Acta Mathematica. pp.135-157. http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203152975702892.