- Vera , Luis Cervera . 1977 . Inventario de los bienes de Juan de Herrera Valencia
- The medieval tradition of the problem is discussed in a valuable article that Luigi Maierù seems to have overlooked: Freudenthal Gad Maimonides' Guide of the Perplexed and the Transmission of the Mathematical Tract “On Two Asymptotic Lines” in the Arabic, Latin and Hebrew Medieval Traditions Vivarium 1988 26 113 140