Donald Fenna (2002)۔ A Dictionary of Weights, Measures, and Units۔ New York: Oxford University Press۔ ص 90& 202۔ ISBN:978-0198605225; "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."
