Slayman, Andrew (27 May 1998). "Neolithic Skywatchers". Archaeology Magazine Archive. Archived from the original on 5 June 2011. Retrieved 17 April 2011.
(Boyer 1991, "The Arabic Hegemony" pp. 241–242) "Omar Khayyam (c. 1050–1123), the "tent-maker," wrote an Algebra that went beyond that of al-Khwarizmi to include equations of third degree. Like his Arab predecessors, Omar Khayyam provided for quadratic equations both arithmetic and geometric solutions; for general cubic equations, he believed (mistakenly, as the 16th century later showed), arithmetic solutions were impossible; hence he gave only geometric solutions. The scheme of using intersecting conics to solve cubics had been used earlier by Menaechmus, Archimedes, and Alhazan, but Omar Khayyam took the praiseworthy step of generalizing the method to cover all third-degree equations (having positive roots). .. For equations of higher degree than three, Omar Khayyam evidently did not envision similar geometric methods, for space does not contain more than three dimensions, ... One of the most fruitful contributions of Arabic eclecticism was the tendency to close the gap between numerical and geometric algebra. The decisive step in this direction came much later with Descartes, but Omar Khayyam was moving in this direction when he wrote, "Whoever thinks algebra is a trick in obtaining unknowns has thought it in vain. No attention should be paid to the fact that algebra and geometry are different in appearance. Algebras are geometric facts which are proved."". Boyer, C.B. (1991) [1989]. A History of Mathematics (Second edition, revised by Uta C. Merzbach ed.). New York: Wiley. ISBN978-0-471-54397-8.
Russell M. Cummings; Scott A. Morton; William H. Mason; David R. McDaniel (2015). Applied Computational Aerodynamics. Cambridge University Press. p. 449. ISBN978-1-107-05374-8. Archived from the original on 1 September 2021. Retrieved 20 September 2019.
Nihat Ay; Jürgen Jost; Hông Vân Lê; Lorenz Schwachhöfer (2017). Information Geometry. Springer. p. 185. ISBN978-3-319-56478-4. Archived from the original on 24 December 2019. Retrieved 23 September 2019.
Robin M. Green; Robin Michael Green (1985). Spherical Astronomy. Cambridge University Press. p. 1. ISBN978-0-521-31779-5. Archived from the original on 21 December 2019. Retrieved 25 September 2019.
Jon Rogawski; Colin Adams (2015). Calculus. W. H. Freeman. ISBN978-1-4641-7499-5. Archived from the original on 1 January 2020. Retrieved 25 September 2019.
Depuydt, Leo (1 January 1998). "Gnomons at Meroë and Early Trigonometry". The Journal of Egyptian Archaeology. 84: 171–180. doi:10.2307/3822211. JSTOR3822211.
Kurt Von Fritz (1945). "The Discovery of Incommensurability by Hippasus of Metapontum". Classics in the History of Greek Mathematics. Annals of Mathematics; Boston Studies in the Philosophy of Science. Vol. 240. Annals of Mathematics, Trustees of Princeton University on Behalf of the Annals of Mathematics, Mathematics Department, Princeton University. pp. 211–231. doi:10.1007/978-1-4020-2640-9_11. ISBN978-90-481-5850-8. JSTOR1969021. {{cite book}}: ISBN / Date incompatibility (help)
Depuydt, Leo (1 January 1998). "Gnomons at Meroë and Early Trigonometry". The Journal of Egyptian Archaeology. 84: 171–180. doi:10.2307/3822211. JSTOR3822211.
Kurt Von Fritz (1945). "The Discovery of Incommensurability by Hippasus of Metapontum". Classics in the History of Greek Mathematics. Annals of Mathematics; Boston Studies in the Philosophy of Science. Vol. 240. Annals of Mathematics, Trustees of Princeton University on Behalf of the Annals of Mathematics, Mathematics Department, Princeton University. pp. 211–231. doi:10.1007/978-1-4020-2640-9_11. ISBN978-90-481-5850-8. JSTOR1969021. {{cite book}}: ISBN / Date incompatibility (help)
Gerla, G. (1995). "Pointless Geometries"(PDF). In Buekenhout, F.; Kantor, W. (eds.). Handbook of incidence geometry: buildings and foundations. North-Holland. pp. 1015–1031. Archived from the original(PDF) on 17 July 2011.
Slayman, Andrew (27 May 1998). "Neolithic Skywatchers". Archaeology Magazine Archive. Archived from the original on 5 June 2011. Retrieved 17 April 2011.
Gerla, G. (1995). "Pointless Geometries"(PDF). In Buekenhout, F.; Kantor, W. (eds.). Handbook of incidence geometry: buildings and foundations. North-Holland. pp. 1015–1031. Archived from the original(PDF) on 17 July 2011.
Russell M. Cummings; Scott A. Morton; William H. Mason; David R. McDaniel (2015). Applied Computational Aerodynamics. Cambridge University Press. p. 449. ISBN978-1-107-05374-8. Archived from the original on 1 September 2021. Retrieved 20 September 2019.
Nihat Ay; Jürgen Jost; Hông Vân Lê; Lorenz Schwachhöfer (2017). Information Geometry. Springer. p. 185. ISBN978-3-319-56478-4. Archived from the original on 24 December 2019. Retrieved 23 September 2019.
Robin M. Green; Robin Michael Green (1985). Spherical Astronomy. Cambridge University Press. p. 1. ISBN978-0-521-31779-5. Archived from the original on 21 December 2019. Retrieved 25 September 2019.
Jon Rogawski; Colin Adams (2015). Calculus. W. H. Freeman. ISBN978-1-4641-7499-5. Archived from the original on 1 January 2020. Retrieved 25 September 2019.