Fenna, Donald (2002). A Dictionary of Weights, Measures, and Units. New York: Oxford University Press. էջեր 90& 202. ISBN978-0198605225.;"Fibonacci, in a book of 1202, brought the Indo-Arabic numerals, with their zero cypher and decimal point, into European culture."; "... these characters are more appropriately called at least Indo-Arabic numerals."
Bulliet, Richard; Crossley, Pamela; Headrick,, Daniel; Hirsch, Steven; Johnson, Lyman (2010). The Earth and Its Peoples: A Global History, Volume 1. Cengage Learning. էջ 192. ISBN1439084742. «Indian mathematicians invented the concept of zero and developed the "Arabic" numerals and system of place-value notation used in most parts of the world today»{{cite book}}: CS1 սպաս․ հավելյալ կետադրություն (link)
O'Connor, J.J. and E.F. Robertson. 2000. Indian NumeralsԱրխիվացված 2007-09-29 Wayback Machine, MacTutor History of Mathematics Archive, School of Mathematics and Statistics, University of St. Andrews, Scotland.
web.archive.org
O'Connor, J.J. and E.F. Robertson. 2000. Indian NumeralsԱրխիվացված 2007-09-29 Wayback Machine, MacTutor History of Mathematics Archive, School of Mathematics and Statistics, University of St. Andrews, Scotland.
