The generating function of bivariate Chebyshev polynomials associated   with the Lie algebra $G_2$
  The generating function of the second kind bivariate Chebyshev polynomials associated with the simple Lie algebra $G_2$ is constructed by the method proposed in \cite{DKS} and \cite{DKS1}. 
E.V. Damaskinsky, M.A. Sokolov
math-ph math.MP