Colville Jeffrey Keith. The structure of Mesoamerican numeral systems with a comparison to non-Mesoamerican systems

Ann Arbor: UMI, N.A., 1985. — 910 p.The vigesimal numeral system is one of the defining features of Mesoamerica as a culture area. Although it also occurs in other areas of the world, including non-Mesoamerican North and South America, the decimal system predominates in the Western Hemisphere. Upon a closer
examination of the numeral systems it becomes apparent that the Mesoamerican vigesimal system assumes two different general forms.