@inproceedings{arlan1974nontransitive,
title={Nontransitive quasi-orbits in Mackey's analysis of group extensions},
author={Arlan Ramsay},
url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203240067731205},
booktitle={Acta Mathematica},
volume={137},
number={1},
pages={17-48},
year={1974},
}
Arlan Ramsay. Nontransitive quasi-orbits in Mackey's analysis of group extensions. 1974. Vol. 137. In Acta Mathematica. pp.17-48. http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203240067731205.