《宋史·列传·卷五十四》
孙甫说： 交子可以伪造，钱也可以私人铸造，难道因为有人敢犯法私铸铁币，就可以将钱币废除吗？
甫曰： 交子可以伪造，钱亦可以私铸，私铸有犯，钱可废乎？
Sun Fu said: Since counterfeit exchange certificates exist, another coin should also be privately minted. Will you abolish coins because someone dared to illegally mint iron coins?