\[R_{G}\left(0,y,z\right)=\tfrac{1}{4}\pi R_{\frac{1}{2}}\left(\tfrac{1}{2},%
\tfrac{1}{2};y,z\right)=\tfrac{1}{4}\pi zR_{-\frac{1}{2}}\left(-\tfrac{1}{2},%
\tfrac{3}{2};y,z\right).\]