1. A. Borel,Introduction aux groupes arithmétiques, Paris, Hermann (1969).
2. A. Borel,Linear algebraic groups, New York, Benjamin (1969).
3. M. Gromov, Hyperbolic manifolds according to Thurston and Jorgensen,Lecture Notes in Mathematics,842, Springer-Verlag (1981), pp. 40–54.
4. M. Gromov,Rigid transformation groups. To appear.
5. V. S. Makarov, On a certain class of discrete Lobachevsky space groups with infinite fundamental domain of finite measure,Dokl. Ak. Nauk. U.S.S.R.,167 (1966), pp. 30–33.