@inproceedings{matthias1991$hp$^{2}-bundles,
title={$HP$^{2}-bundles and elliptic homology},
author={Matthias Kreck, and Stephan Stolz},
url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203320918141490},
booktitle={Acta Mathematica},
volume={171},
number={2},
pages={231-261},
year={1991},
}
Matthias Kreck, and Stephan Stolz. $HP$^{2}-bundles and elliptic homology. 1991. Vol. 171. In Acta Mathematica. pp.231-261. http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203320918141490.