Kh.Abbas, H., A. Hassan M.Al-saleh, and A. A. D.AL-Zuky. “Determine the Best Mathematical Model for the Camera Viewing Angle As a Function of Object Distance”. Mustansiriyah Journal for Sciences and Education, vol. 17, no. 3, Sept. 2020, pp. 47-54, https://edumag.uomustansiriyah.edu.iq/index.php/mjse/article/view/149.