@inproceedings{r.1971deformations,
title={Deformations of lie subgroups and the variation of isotropy subgroups},
author={R. W. Richardson Jr.},
url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203225426706135},
booktitle={Acta Mathematica},
volume={129},
number={1},
pages={35-73},
year={1971},
}
R. W. Richardson Jr.. Deformations of lie subgroups and the variation of isotropy subgroups. 1971. Vol. 129. In Acta Mathematica. pp.35-73. http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203225426706135.