@inproceedings{bob2000fixed, title={Fixed point free actions on$Z$-acyclic 2-complexes}, author={Bob Oliver, and Yoav Segev}, url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203341300844631}, booktitle={Acta Mathematica}, volume={189}, number={2}, pages={203-285}, year={2000}, }