On the basis of fundamental Nevanlinna theory the problem of normality of meromorphic functions that share three finite complex values with their k-th derivatives (k is any positive integer)is discussed and some examples are provided to show the result is sharp.
Qing De ZHANG; Chun Yan Qin.
Normal Familles and Shared Values of Meromorphic Functions. Acta Mathematica Sinica, Chinese Series, 2008, 51(1): 145-152 https://doi.org/10.12386/A2008sxxb0018