1. Goluzin, G.M. Geometric theory of functions of a complex variables. AMS Translations of Mathematical Monographs. Vol. 26. AMS (Providence, Rhode Island, 1969).
2. Nehari, Z. “The Schwarzian derivatives and schlicht functions”, Bull. Amer. Math. Soc. 55(6), 545–551 (1949).
3. Ahlfors, L., Weill, G. “A uniqueness theorem for Beltrami equations”, Proc. Amer. Math. Soc. 13(6), 975–978 (1962).
4. Ahlfors, L. “Cross-ratios and Schwarzian derivatives in ℝn” (in: Complex Analysis: Articles Dedicated to Albert Pfluger on the Occasion of his 80th Birthday, Hersch J. and Huber A., Eds., 1–15, Birkhäuser Verlag, Basel (1989)).
5. Duren, P. Harmonic mappings in the plane. (Cambridge Univ. Press, Cambridge, 2004).