\[F_{\ell}\left(\eta,\rho\right)=C_{\ell}\left(\eta\right)\frac{(2\ell+1)!}{(2%
\left|\eta\right|)^{2\ell+1}}\rho^{-\ell}\*\sum_{k=2\ell+1}^{\infty}\!\!b_{k}t%
^{k/2}J_{k}\left(\textstyle 2\sqrt{t}\right),\]