\[\mathcal{K}(z,t)=(zt-a)^{\frac{1}{2}-\delta-\sigma}\*{{}_{2}F_{1}}\left({\frac%
{1}{2}-\delta-\sigma+\alpha,\frac{1}{2}-\delta-\sigma+\beta\atop\gamma};\frac{%
zt}{a}\right)\*{{}_{2}F_{1}}\left({-\frac{1}{2}+\delta+\sigma,-\frac{1}{2}+%
\epsilon-\sigma\atop\delta};\frac{a(z-1)(t-1)}{(a-1)(zt-a)}\right),\]