Several properties of $\alpha$-harmonic functions in the unit disk
  The aim of this paper is to obtain the Schwarz-Pick type inequality for $\alpha$-harmonic functions $f$ in the unit disk and get estimates on the coefficients of $f$. As an application, a Landau type theorem of $\alpha$-harmonic functions is established. 
Peijin Li, Xiantao Wang and Qianhong Xiao
math.CV