1. F. Bagemihl,Horocyclic boundary properties of meromorphic functions, Ann. Acad. Scient. Fenn, A-1 (385) (1966), 1–18.
2. F. Bagemihl and W. Seidel,Behavior of meromorphic functions on boundary paths with applications to normal functions, Arch. Math.11 (1960), 263–269.
3. E. Hille,Analytic Function Theory, Vol. II, 1963.
4. C. Kuratowski, Topologie, Vol. II. Monografie Matematyczne, Warszawa, 1961.
5. P. Lappan,Thesis, Notre Dame, 1963.