Azarian, Mohammad K. (2010). "al-Risāla al-muhītīyya: A Summary". Missouri Journal of Mathematical Sciences. 22 (2): 64–85. doi:10.35834/mjms/1312233136.
Bartholomew, Randyn Charles. Let’s Use Tau—It’s Easier Than Pi (angle). Scientific American (2014-06-25). Alirita 2017-09-23 . “Interestingly, Archimedes did not use the Greek letter π. That didn't come until Swiss mathematician Leonhard Euler popularized the convention in 1736,...”.
st-andrews.ac.uk
mathshistory.st-andrews.ac.uk
O'Connor, John J.; Robertson, Edmund F. (1999). "Ghiyath al-Din Jamshid Mas'ud al-Kashi". MacTutor History of Mathematics archive. Arkivita el la originalo la 12an de Aprilo 2011. Alirita la 11an de Aŭgusto 2012.
