《后汉书·列传·郑范陈贾张列传》
世上谈《左氏》的多半以郑兴为祖。而贾逵自传其父业，所以有郑、贾之学的说法。
世言《左氏》者多祖于兴，而贾逵自传其父业，故有郑、贾之学。
Most people who talked about "Zuo" in the world referred to Zheng Xing as their predecessor, and Jia Kui himself inherited his father's cause, so people talked about Zheng and Jia's learning.