1. [A1] L.V. Ahlfors, An extension of Schwarz's lemma, Trans. Amer. Math. Soc. 43 (1938), 359–364.
2. [A2] L.V. Ahlfors, Conformal invariants: Topics in geometric function theory, McGraw Hill, New York, 1973.
3. L.V. Ahlfors, H. Grunsky, Über die Blochsche Konstante, Math. Z. 42 (1937), 671–673.
4. M. Bonk, On Bloch's constant, Proc. Amer. Math. Soc. (to appear).
5. C. Carathéodory, Theory of functions of a complex variable, vol. II, 2nd English ed., Chelsea Publishing Co., New York, 1960.