1. L. R. Ford, Automorphic functions, McGraw-Hill, New York, 1929.
2. Attractive fixed points and continued fractions;Gill, John;Math. Scand.,1973
3. Infinite compositions of Möbius transformations;Gill, John;Trans. Amer. Math. Soc.,1973
4. Continued fraction approximation to functions;Hayden, T. L.;Numer. Math.,1965
5. A. N. Hovanskiĭ, The application of continued fractions and their generalizations to problems in approximation theory, GITTL, Moscow, 1956