Formula_6468

\[\begin{gathered}A(s, t)=\frac{1}{\pi^{2}} \iint d s^{\prime} d t^{\prime} \frac{\rho_{s t}\left(s^{\prime}, t^{\prime}\right)}{\left(s^{\prime}-s\right)\left(t^{\prime}-t\right)}+ \\+\frac{1}{\pi^{2}} \iint d u^{\prime} d t^{\prime} \frac{\rho_{u t}\left(u^{\prime}, t^{\prime}\right)}{\left(u^{\prime}-u\right)\left(t^{\prime}-t\right)}+\frac{1}{\pi^{2}} \iint d u^{\prime} d s^{\prime} \frac{\rho_{s u}\left(s^{\prime}, u^{\prime}\right)}{\left(u^{\prime}-u\right)\left(s^{\prime}-s\right)},\end{gathered}\]