Moment generating function of a bivariate normal distribution?

MX,Y(s,t) = exp{μxs + μYt + ½(σX2s2 + 2ρσXσYst + σY2t2)} Where X ~ N (μx , σX) and Y ~ N (μY , σY). Also Corr(X,Y) = Cov (X,Y)/{Var(X) . Var(Y)} = ρ