On the Asymptotic Behavior of Functions Harmonic in a Disc
J. E. McMillan · Nagoya Mathematical Journal · 1966
Let D be the open unit disc, and let C be the unit circle in the complex plane. Let f be a (real-valued) function that is harmonic in D. A simple continuous curve β: z(t) (0≦t<1) contained in D such that |z(t)|→1 as t→1 is a boundary path with end (the bar denotes closure).