I'm going to be giving an informal presentation on this event by the end of this month and could use some recommendations. I've got a biography on Constantine XI and Mehmed II along with some general reading on the Byzantine Empire and it's decline but none of these works so far provide an in-depth, retrospective account of the battle itself from both sides in terms of tactics, equipment fielded by respective armies and the general progression of the siege. I know mainly how it started and ended, but not the in between.