《资治通鉴·齐纪·齐纪三》
人们之所以很容易地就能偷偷伪造钱币，连严格的法令都禁止不了，就是因为官府铸钱时，过于珍惜铜，又不能精心加工的缘故。
民所以盗铸，严法不能禁者，由上铸钱惜铜爱工也。
The reason why people can easily make counterfeit money, even if strict laws prohibit it, is because when the government mints money, it cares too much about copper and cannot refine it.