He has refused the publication of spin-off novels and comic books that have tried to definitively link the two.
However, some of the spin-off novels and short stories add to her history.
This includes a graphic novel, several spin-off novels, and an official soundtrack release.
Flynn would go on to appear in four of his own spin-off novels.
As of March 2013, 10 main volumes and a spin-off novel have been published.
The canonicity of the spin-off novels is open to interpretation.
A spin-off novel, Maniwagatari, was released a few months later.
This is the first time any of the spin-off novels have been referenced on-screen.
Several of the spin-off novels have further information about Gallifrey.
Various spin-off novels have expanded on the history and nature of Gallifrey.