@inproceedings{clifford1970on,
title={On the joint distribution of crossing of high multiple levels by a stationary gaussian process},
author={Clifford Qualls},
url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203444198804128},
booktitle={Arkiv for Matematik},
volume={8},
number={2},
pages={129-137},
year={1970},
}
Clifford Qualls. On the joint distribution of crossing of high multiple levels by a stationary gaussian process. 1970. Vol. 8. In Arkiv for Matematik. pp.129-137. http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203444198804128.