1. L. V. Ahlfors, Conformal Invariants, Topics in Geometric Function Theory, Series in Higher Mathematics, McGraw-Hill Book Co., New York, 1973.
2. D. P. Bellamy and L. Lum, The Cyclic Connectivity of Homogeneous Arcwise Connected Continua, Trans. Amer. Math. Soc., 266 (1981), 389–396.
3. C. H. Dowker, Mapping Theorems for Non-compact Spaces, Amer. J. Math., 69 (1947), 200–242.
4. J. Dugundji, Topology, Allyn and Bacon, Inc., Boston, London, Sydney, Toronto, 1966.
5. R. Engelking, General Topology, Sigma Series in Pure Mathematics, Vol. 6, Heldermann, Berlin, 1989.