By D, D and T we denote, respectively, the open unit disc {|z| < 1}, the closed unit disc {|z| ≤ 1} and the unit circle {|z| = 1} in the complex plane C. A domain is a nonempty connected open subset G ⊂ C. Its one-point compactification G∪ {∞} will be represented by G∞. A domain G ⊂ C is called simply connected provided that C∞ \G is connected. The symbol H(G) will stand for the space of holomorphic functions on G. It becomes an F-space –that is, a complete metrizable topological vector space– under the topology of uniform convergence on compact subsets of G.