  The behavior of correlation functions is studied in a class of matrix models
characterized by a measure $\exp(-S)$ containing a potential term and an
external source term: $S=N\tr(V(M)-MA)$. In the large $N$ limit, the
short-distance behavior is found to be identical to the one obtained in
previously studied matrix models, thus extending the universality of the
level-spacing distribution. The calculation of correlation functions involves
(finite $N$) determinant formulae, reducing the problem to the large $N$
asymptotic analysis of a single kernel $K$. This is performed by an appropriate
matrix integral formulation of $K$. Multi-matrix generalizations of these
results are discussed.
