1. Bogaert, R., Brion, R., Kurgan-Van Hentenryk, G., Moreau, J.-L., & Van Der Wee, H. (2000). La Banque en Occident. Anvers: Fonds Mercator.
2. Carl, M. (1892). On the origins of money. Economic Journal, 2, 239–255.
3. Thomas, S., & François, V. (2002). The big problem of small change. Princeton/Oxford: Princeton University Press.