Hi Clementina,
Congratulations on an interesting topic for your grad. thesis!
As for biographical information on Duncan Jones, I can't remember having read too much. Every biographer tend to talk about him when they cover the writing of the Kooks song on Hunky Dory and possibly also a little bit when discussing Bowie & Angela's divorce. Angela Bowie's autobiography
Backstage Passes talks a fair bit about Duncan, but most of it in regards to the difficult birth and a few anecdotes on his parents costudy over Duncan and such. Nothing, I would immagine, of any real interest to a thesis about Duncon Jones as a filmmaker. I would check out the sources quoted on this wikipadia article: http://en.wikipedia.org/wiki/Duncan_Jones
That's all I can think of at the moment