| 1 | L.S. Pontryagin, Topological groups, Gordon and Breach Science Publishers,1986. |
| 2 | J.W. Anderson, Hyperbolic Geometry, Springer-Verlag, London, 2005. |
| 3 | G.A. Jones and D.Singerman, Complex Functions: an algebraic and geometric viewpoint, Gambridge University Press,1987. |
| 4 | H. Schwerdtfeger, Geometry of Complex Numbers, Dover Publications, New York, 1979. |
| 5 | S. Katok, Fuchsian groups, The University of Chicago Press, 1992. |