"Investigations of the Geographical Directory 1979–2007 "; DIO Archived 2008-03-06 at the Wayback Machine., volume 6, number 1, page 11, note 47, 1996. 1 2 http://www.ias.ac.in/resonance/march2006/p51-68.pdf ↑ "Aryabhata the Elder". ↑ David A. King, Astronomy in the Service of Islam, (Aldershot (U.K.): Variorum), 1993. ↑ 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.