\[W_{\kappa,\mu}\left(z\right)=\frac{2\sqrt{z}e^{-\frac{1}{2}z}}{\Gamma\left(%
\frac{1}{2}+\mu-\kappa\right)\Gamma\left(\frac{1}{2}-\mu-\kappa\right)}\*\int_%
{0}^{\infty}e^{-t}t^{-\kappa-\frac{1}{2}}K_{2\mu}\left(2\sqrt{zt}\right)\,%
\mathrm{d}t,\]