Smith 2001, Book I [6.85], [6.86], p. 379; Book II, [3.80], p. 453. Smith, A. Mark(2001).Alhacen's Theory of Visual Perception: A Critical Edition, with English Translation and Commentary, of the First Three Books of Alhacen's De Aspectibus, the Medieval Latin Version of Ibn al-Haytham's Kitāb al-Manāẓir, 2 vols. Transactions of the American Philosophical Society. "91". Philadelphia: American Philosophical Society. ISBN 978-0-87169-914-5. OCLC47168716.
Smith, A. Mark(2001a).”Alhacen's Theory of Visual Perception: A Critical Edition, with English Translation and Commentary, of the First Three Books of Alhacen's "De aspectibus", the Medieval Latin Version of Ibn al-Haytham's "Kitāb al-Manāẓir": Volume One”.Transactions of the American Philosophical Society91(4): sid.i–clxxxi, 1–337. doi:10.2307/3657358.
Mastin 2010. "Although usually remembered today as a philosopher, Plato was also one of ancient Greece's most important patrons of mathematics. Inspired by Pythagoras, he founded his Academy in Athens in 387 BC, where he stressed mathematics as a way of understanding more about reality. In particular, he was convinced that geometry was the key to unlocking the secrets of the universe. The sign above the Academy entrance read: 'Let no-one ignorant of geometry enter here. Mastin, Luke(2010).”Plato”.Plato. lukemastin.com. http://www.lukemastin.com/storyofmathematics/greek_plato.html.
Smith 2001, Book I [6.85], [6.86], p. 379; Book II, [3.80], p. 453. Smith, A. Mark(2001).Alhacen's Theory of Visual Perception: A Critical Edition, with English Translation and Commentary, of the First Three Books of Alhacen's De Aspectibus, the Medieval Latin Version of Ibn al-Haytham's Kitāb al-Manāẓir, 2 vols. Transactions of the American Philosophical Society. "91". Philadelphia: American Philosophical Society. ISBN 978-0-87169-914-5. OCLC47168716.
Smith, A. Mark(2001a).”Alhacen's Theory of Visual Perception: A Critical Edition, with English Translation and Commentary, of the First Three Books of Alhacen's "De aspectibus", the Medieval Latin Version of Ibn al-Haytham's "Kitāb al-Manāẓir": Volume One”.Transactions of the American Philosophical Society91(4): sid.i–clxxxi, 1–337. doi:10.2307/3657358.