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.