1. W. M. Goldman, Complex hyperbolic geometry. Oxford Univ. Press 1999. MR1695450 Zbl 0939.32024
2. W. M. Goldman, J. R. Parker, Complex hyperbolic ideal triangle groups. J. Reine Angew. Math. 425 (1992), 71–86. MR1151314 Zbl 0739.53055
3. G. H. Hardy, E. M. Wright, An introduction to the theory of numbers. Oxford Univ. Press 2008. MR2445243 Zbl 1159.11001
4. S. Kamiya, Remarks on complex hyperbolic triangle groups. In: Complex analysis and its applications, volume 2 of OCAMI Stud., 219–223, Osaka Munic. Univ. Press, Osaka 2007. MR2405722 Zbl 1144.51002
5. S. Kamiya, J. R. Parker, J. M. Thompson, Notes on complex hyperbolic triangle groups. Conform. Geom. Dyn. 14 (2010), 202–218. MR2718204 Zbl 1220.22004