The origins of the Theorica planetarum / Olaf Pedersen.
Abstract:
The "Theorica planetarum" was used as an astronomy text in medieval universities. The author finds no reason "...strong enough to invalidate the hypothesis that the "Theorica" and its place within the Latin tradition of astronomical manuals are best understood on the assumption that it originated from the hand of a 13th century author" who remains unknown
Journal for the history of astronomy Vol. 12 (1981), p. 113-123