In this case, when we calculate the mutual coherence function for an extended coherent source, we would not be able to simply integrate over the intensity function of the source; the presence of non-zero cross terms would give the mutual coherence function no simple form.
12.
I look at the context of the discussion and I see that the Wolf Effect is not being discussed as a coherent source physical optics phenomena, but rather as an astrophysical context ( in particular the context of nonstandard interpretations of cosmological redshifts-- an interpretation that is found in absolutely no peer-reviewed papers ).
