Hogendijk, Jan, P. (1986). "Discovery of an 11th-century geometrical compilation: The Istikmāl of Yūsuf al-Mu'taman ibn Hūd, King of Saragossa". Historia Mathematica. 13: 43–52. doi:10.1016/0315-0860(86)90227-2.{{cite journal}}: CS1 maint: multiple names: authors list (link)
