Spencer, D. B. (2021) “Numismatic Typeforms of the Numerals Zero through Ten in Medieval Europe: A Classification System”, KOINON: The International Journal of Classical Numismatic Studies, 4, pp. 203–214. Available at: https://archaeopresspublishing.com/ojs/index.php/koinon/article/view/1117 (Accessed: 8 December 2023).