1. M. F. Atiyah, Elliptic operators, discrete groups and von Neumann algebras, Colloque “Analyse et Topologie” en l'Honneur de Henri Cartan (Orsay, 1974), Astérisque, No. 32–33, Soc. Math. France, Paris, 1976, pp. 43–72.
2. J. A. Baglivo, An equivariant Wall obstruction theory, Trans. Amer. Math. Soc. 256 (1979), 305–324.
3. M. Bestvina and N. Brady, Morse theory and finiteness properties of groups, Invent. Math. 129 (1997), no. 3, 445–470.
4. M. R. Bridson and A. Haefliger, Metric spaces of non-positive curvature, Grundlehren der Mathematischen Wissenschaften [Fundamental Principles of Mathematical Sciences], vol. 319, Springer, Berlin, 1999.
5. M. Belolipetsky and A. Lubotzky, Finite groups and hyperbolic manifolds, Invent. Math. 162 (2005), no. 3, 459–472.