@inproceedings{dirk2000on,
title={On the number of bound states for Schrödinger operators with operator-valued potentials},
author={Dirk Hundertmark},
url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203603727693784},
booktitle={Arkiv for Matematik},
volume={40},
number={1},
pages={73-87},
year={2000},
}

Dirk Hundertmark. On the number of bound states for Schrödinger operators with operator-valued potentials. 2000. Vol. 40. In Arkiv for Matematik. pp.73-87. http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203603727693784.