How do I solve the lower integration of spherical harmonics, in terms of Clebsch Gordon coefficients?
\begin{equation} \int d\Omega Y^{l_1}_{m_1}(\hat n)Y^{l_2}_{m_2}(\hat n){Y^{l}_m}^*(\hat n) \end{equation}
As a side note, where could I find derived properties of spherical harmonics and Clebsch Gordon coefficients?