James S. Aber (2003). Alberuni calculated the Earth's circumference at a small town of Pind Dadan Khan, District Jhelum, Punjab, Pakistan.Abu Rayhan al-Biruni, Emporia State University.
“The Round Earth”. NASA (12 December 2004). 24 January 2008閲覧。
ox.ac.uk
bodley.ox.ac.uk
Gharā'ib al-funūn wa-mulah al-`uyūn (The Book of Curiosities of the Sciences and Marvels for the Eyes), 2.1 "On the mensuration of the Earth and its division into seven climes, as related by Ptolemy and others," (ff. 22b-23a)[3]
Strabo (1960) [1917]. The Geography of Strabo, in Eight Volumes. Loeb Classical Library edition, translated by Horace Leonard Jones, A.M., Ph.D.. London: William Heinemann, Vol.I Bk. I para. 20, pp. 41, 43. An earlier edition is available online.