@inproceedings{m.1978concordance,
title={Concordance classes of regular$O(n)$-actions on homotopy spheres},
author={M. Davis, W. C. Hsiang, and J. W. Morgan},
url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203251347639274},
booktitle={Acta Mathematica},
volume={144},
number={1},
pages={153-221},
year={1978},
}
M. Davis, W. C. Hsiang, and J. W. Morgan. Concordance classes of regular$O(n)$-actions on homotopy spheres. 1978. Vol. 144. In Acta Mathematica. pp.153-221. http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203251347639274.