Uniqueness of entire functions

Let f be a nonconstant entire function and let a be a meromorphic function satisfying T (r,a) = S(r,f ) and a ≡ a . If f (z) = a(z)⇔f (z) = a(z) and f (z) = a(z)⇒f (z) = a(z), then f ≡ f , and a ≡ a is necessary. This extended a result due to Jank, Mues and Volkmann.  2003 Elsevier Inc. All rights reserved