@inproceedings{sigurdur1964the,
title={The Radon transform on Euclidean spaces, compact two-point homogeneous spaces and Grassmann manifolds},
author={Sigurdur Helgason},
url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203205715975990},
booktitle={Acta Mathematica},
volume={113},
number={1},
pages={153-180},
year={1964},
}
Sigurdur Helgason. The Radon transform on Euclidean spaces, compact two-point homogeneous spaces and Grassmann manifolds. 1964. Vol. 113. In Acta Mathematica. pp.153-180. http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203205715975990.