In the case of Invasion, references have been made to it, but as far as I know (something tells me someone may prove me wrong), no references have been made to Millennium, nor did it reference anything else.
I can't think of a reference to Millennium
in the larger Lit-verse, and I don't believe it referenced anything. If I remember correctly, Marco's view on Millennium
was the same as his view on A Stitch In Time
; the books weren't part of the DS9
relaunch proper but they were as valid a part of the relaunch universe as the television series itself.