PUSTAKA
https://www.romadecade.org/sejarah-uang/
https://uangindonesia.com/tentang-uang-pengertian-sejarah-fungsi-syarat-jenis-dan-teorinya/
https://moondoggiesmusic.com/sejarah-uang/
https://salamadian.com/pengertian-fungsi-syarat-sejarah-uang/
http://boma-internet.blogspot.com/2011/12/sejarah-uang-dan-pengertian-uangmateri.html