Sigfried J. de Laet (1994). History of Humanity: From the seventh to the sixteenth century. UNESCO, გვ. 931. ISBN978-92-3-102813-7. „The science of trigonometry as known today was established by Islamic mathematicians. One of the most important of these was the Persian Abu' l-Wafa' Buzjani (d. 997 or 998), who wrote a work called the Almagest dealing mostly with trigonometry“
