Bulliet,Richard;Crossley,Pamela;Headrick,Daniel;Hirsch,Steven;Johnson,Lyman(2010).The Earth and Its Peoples: A Global History, Volume 1.Cengage Learning.str.192.ISBN978-1-4390-8474-8.»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«