Analysis of information sources in references of the Wikipedia article "Coinage metals" in English language version.
The idea of coinage follows almost naturally from the use of metal as a commodity for exchange. [...] Graeber [...] connects the Axial Age to the first coinage, noting that the three parts of the world where coins were first used correspond to the very parts of the world where religious and philosophical creativity thrived, that is, the kingdoms and city-states around the shores of the Aegean Sea, in the Ganges valley in northern India, and around the Yellow River in China [...].
