@inproceedings{hans2002an,
title={An explicit inversion formula for the exponential Radon transform using data from 180°},
author={Hans Rullgård},
url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203611948465848},
booktitle={Arkiv for Matematik},
volume={42},
number={2},
pages={353-362},
year={2002},
}

Hans Rullgård. An explicit inversion formula for the exponential Radon transform using data from 180°. 2002. Vol. 42. In Arkiv for Matematik. pp.353-362. http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203611948465848.