1. [B1] A. Borel, Cohomologie de sous-groupes discrets et représentations de groupes semi-simples, Colloque “Analyse et Topologie” en l'Honneur de Henri Cartan (Orsay, 1974), Soc. Math. France, Paris, 1976, 73–112. Astérisque, No. 32-33.
2. [B2] A. Borel, Compact Clifford-Klein forms of symmetric spaces, Topology 2 (1963), 111–122.
3. [B3] A. Borel, Density properties for certain subgroups of semi-simple groups without compact components, Ann. of Math. (2) 72 (1960), 179–188.
4. [Br1] R. Brooks, Injectivity radius and low eigenvalues of hyperbolic manifolds, J. Reine Angew. Math. 390 (1988), 117–129.
5. [Br2] R. Brooks, Some remarks on volume and diameter of Riemannian manifolds, J. Differential Geometry 27 (1988), no. 1, 81–86.