Lin, Wei Chuan et Yi, Hong Xun, On Homogeneous Differential Polynomials of Meromorphic Functions, Acta mathematica Sinica. English series (Print) , 21(2), 2004, pp. 261-266
In this paper, we study one conjecture proposed by W. Bergweiler and show that any transcendental meromorphic functions f(z) have the form exp(z*) if f(z)f(z)a(f (z))20, where a1,n1n,nN. Moreover, an analogous normality criterion is obtained.