There's a Trek-as-TV reference in The Rings of Time, when Zoe speculates about "sexy green girls."
Well, in-universe that could be a reference to other science fiction, since ST never had a monopoly on green alien women. After all, it's a natural extension of the "little green men" trope that's been around since the early 20th century. There was a green alien temptress who appeared in two Lost in Space
episodes, for example.
Not mention various Skrull females in The Fantastic Four, Gamora from the old ADAM WARLOCK comics, the Impossible Woman, etc.
Certainly, I was making a Trek in-joke there, but I thought that the concept of sexy green-skinned alien babes was generic enough that I wasn't explicitly saying that Trek existed as TV show in that universe.