1. Blažek, V. (1999). Numerals: Comparative etymological analyses and their implications: Saharan, Nubian, Egyptian, Berber, Kartvelian, Uralic, Altaic and Indo-European languages. Brno: Masarykova Univerzita.
2. Cammarosano, M. (2014). The cuneiform stylus. Mesopotamia: Rivista di archeologia, epigrafia e storia orientale antica, XLIX, 53–90.
3. Chrisomalis, S. (2010). Numerical notation: A comparative history. Cambridge: Cambridge University Press.
4. Coinman, N. R. (1996). Worked bone in the Levantine Upper Paleolithic: Rare examples from the Wadi al-Hasa, West-Central Jordan. Paléorient, 22(2), 113–121.
5. Comrie, B. (2013). Numeral bases. In M. S. Dryer & M. Haspelmath (Eds.), World atlas of language structures online. Leipzig: Max Planck Institute for Evolutionary Anthropology.
http://wals.info/chapter/131
. Accessed 3 Aug 2017.