@inproceedings{anders1968a,
title={A problem of newman on the eigenvalues of operators of convolution type},
author={Anders Wik},
url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203442555463113},
booktitle={Arkiv for Matematik},
volume={7},
number={6},
pages={601-605},
year={1968},
}
Anders Wik. A problem of newman on the eigenvalues of operators of convolution type. 1968. Vol. 7. In Arkiv for Matematik. pp.601-605. http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203442555463113.