\begin{thebibliography}{{Led}09} \bibitem[{Led}09]{2009arXiv0910.1425L} F.~{Ledrappier}. \newblock {Linear drift and entropy for regular covers}. \newblock {\em ArXiv e-prints}, October 2009. \bibitem[{Les}10]{2010arXiv1001.0053L} P.~{Lessa}. \newblock {Rotation Vectors for Homeomorphisms of Non-Positively Curved Manifolds}. \newblock {\em ArXiv e-prints}, December 2010. \end{thebibliography}