《旧唐书·列传·卷一百一十九》
大和七年，郑注被免去宁行军司马，召入京师，御史李款于紫宸殿弹劾他道： 郑注内通敕使，外结朝官，两地往来，牟取财货，昼伏夜动，窃位求权。
太和七年，罢邠宁行军司马，入京师。御史李款阁内弹之曰： 郑注内通敕使，外结朝官，两地往来，卜射财货，昼伏夜动，干窃化权。
In the seventh year of Daye, Zheng Zhu was dismissed from the post of Sima of Ningxing Army, and was summoned to the capital, the censor Li Kuan impeached him in Zichen hall: Zheng Zhu communicated with the envoy internally, and colluded with the court officials externally, he traveled between the two places to make money, and he was in power and sought power by acting sneaky.