I've checked carefully in PT:LOS for the section I thought I remembered, but I can't find it. I distinctly remember the form of the theorem (it was a squeeze theorem), but I do not recall where I saw it. I think Jaynes was the author, so it might be in one of the papers listed here... or it could have been someone else entirely, or I could be misremembering. But I don't think I'm misremembering, because I recall working through the proof and becoming satisfied that Uffink must have made a coding error.