《后汉书·列传·郑范陈贾张列传》
九岁时读了《论语》、《孝经》，年长时，学习《梁丘易》、《老子》，并教授后生学习。
九岁通《论语》、《孝经》，及长，习《梁丘易》、《老子》，教授后生。
At the age of nine, he read "The Analects" and "The Canon of Filial Piety", and when he was older, he studied "Liang Qiu Yi" and "Lao Zi", and taught the younger generation to learn.