Coefficient estimates for bi-univalent Ma-Minda starlike and convex   functions
  Estimates on the initial coefficients are obtained for normalized analytic functions $f$ in the open unit disk with $f$ and its inverse $g=f^{-1}$ satisfying the conditions that $zf'(z)/f(z)$ and $zg'(z)/g(z)$ are both subordinate to a starlike univalent function whose range is symmetric with respect to the real axis. Several related classes of functions are also considered, and connections to earlier known results are made. 
Rosihan M. Ali, Lee See Keong, V. Ravichandran, Shamani Supramaniam
math.CV