- You may be looking for the real world publisher.
The Doctor's universe
While the Fourth Doctor worked for UNIT, he wrote a series of educational children's books. It was intended to be called The Doctor, Who Discovers... but the publisher misprinted the covers as Doctor Who Discovers. (AUDIO: The Kingmaker)
The Eighth Doctor found a copy of a Target novel, Doctor Who in an Exciting Adventure with the Daleks, inside Iris Wildthyme's TARDIS, which he claimed contradicted another title in the series. (PROSE: Bafflement and Devotion)
Godfrey Porter's world
Behind the scenes
Information from invalid stories
The Complete Guide to Doctor Who?