On Interbasis Expansion for Isotropic Oscillator on Two-Dimensional   Sphere
  In this article we analyze the isotropic oscillator system on the two-dimensional sphere in the spherical systems of coordinates. The expansion coefficients for transitions between three spherical bases of the oscillator are calculated. It is shown that these coefficients are expressed through the Clebsch-Gordan coefficients for SU(2) group analytically continued to real values of their argument. 
Ye.M. Hakobyan, G.S. Pogosyan