"Annals of Emperor Wu" and "Treatise on Food and Money" in Ban Gu's "Book of Han", and "Treatise on Food and Money, Part 1" in the "Old Book of Tang" (on the introduction and abolition of the Wuzhu coin).

Claims Supported by This Source

1. In the third month of the spring of the fifth year of the Yuanshou era, the Ban Liang coin was abolished and the Wu Zhu coin was introduced (Annals of Emperor Wu).
2. A rim was added to the edge to prevent filing. From the fifth year of the Yuanshou era to the Yuanshi era of Emperor Ping, over 28 billion were minted (Treatise on Food and Money).
3. In the seventh month of the fourth year of the Wude era, the Wu Zhu coin was abolished and the Kaiyuan Tongbao was introduced ("Old Book of Tang," Treatise on Food and Money, Part 1).

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