  Partition- and moment functions for a general (not necessarily Gaussian)
functional measure that is perturbed by a Gibbs factor are calculated using
generalized Feynman graphs. From the graphical calculus, a new notion of Wick
ordering arises, that coincides with orthogonal decompositions of Wiener-It\^o
\~type only if the measure is Gaussian. Proving a generalized linked cluster
theorem, we show that the logarithm of the partition function can be expanded
in terms of connected Feynman graphs ("linked cluster theorem").
