A. Mark Smith (2007) "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-Haytam's Kitab al-Manazir. Volume One. " Transactions of the American Philosophical SocietyVolume 91, part 4JSTOR3657358
(see p. clxviii) has found that there were at least two translators from Ibn al-Haytam's Kitab al-Manazir (in Arabic) to Alhacen's De Aspectibus (in Latin), one of them a master as skilled as Gerard of Cremona, and the other(s) less skilled.