@inproceedings{bob2011existence,
title={Existence and uniqueness of linking systems: Chermak’s proof via obstruction theory},
author={Bob Oliver},
url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203401160998774},
booktitle={Acta Mathematica},
volume={211},
number={1},
pages={141-175},
year={2011},
}
Bob Oliver. Existence and uniqueness of linking systems: Chermak’s proof via obstruction theory. 2011. Vol. 211. In Acta Mathematica. pp.141-175. http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203401160998774.