Ibn Labbān, Kūshyār (1965). Kitab fi usul hisab al-hind [Principles of Hindu Reckoning]. Translated by Levey, Martin; Petruck, Marvin. Madison: University of Wisconsin Press. էջ 3. ISBN978-0-299-03610-2.
William Darrach Halsey, Emanuel Friedman (1983). Collier's Encyclopedia, with bibliography and index. «When the Arabian empire was expanding and contact was made with India, the Hindu numeral system and the early algorithms were adopted by the Arabs»