《北齐书·列传·卷二十九》
人们歌颂他们说： 大郑公，小郑公，相距五十年，风俗教化还一样。 
人歌之曰： 大郑公，小郑公，相去五十载，风教犹尚同。 
The people praised them, saying, "great Zheng Gong, young Zheng Gong, after fifty years, the folk customs and teachings are still the same."