@inproceedings{i.1985on,
title={On the classification of$G$-spheres I: equivariant transversality},
author={I. Madsen, and M. Rothenberg},
url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203309694034411},
booktitle={Acta Mathematica},
volume={160},
number={1},
pages={65-104},
year={1985},
}
I. Madsen, and M. Rothenberg. On the classification of$G$-spheres I: equivariant transversality. 1985. Vol. 160. In Acta Mathematica. pp.65-104. http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203309694034411.