King, David A. (2005). „The Sacred Geography of Islam”. Ур.: Koetsier, Teun; Luc, Bergmans. Mathematics and the Divine: A Historical Study. Amsterdam: Elsevier. стр. 162—78. ISBN0-444-50328-5.
King (2005, p. 169). The calculations were as accurate as could be achieved under the limitations imposed by their assumption that the Earth was a perfect sphere.
ccrma-stanford.edu
Smith, Julius O. (2003). „Euler's Identity”. Mathematics of the Discrete Fourier Transform (DFT). W3K Publishing. ISBN0-9745607-0-7. Архивирано из оригинала 2006-09-15. г. Приступљено 2006-09-22.
Smith, Julius O. (2003). „Euler's Identity”. Mathematics of the Discrete Fourier Transform (DFT). W3K Publishing. ISBN0-9745607-0-7. Архивирано из оригинала 2006-09-15. г. Приступљено 2006-09-22.