\[C_{m,\ell}(\alpha,\beta)={\left(\tfrac{1}{2}+\alpha\right)_{\ell}}{\left(%
\tfrac{1}{2}-\alpha\right)_{\ell}}{\left(\tfrac{1}{2}+\beta\right)_{m-\ell}}{%
\left(\tfrac{1}{2}-\beta\right)_{m-\ell}},\]