《新唐书·列传·卷一百二十九》
父严延，与河东裴玄证、陇西李真、蔡静等人都通儒术，通晓图谶。
父延，与河东裴玄证、陇西李贞蔡静皆通儒术，该晓图识。
His father, Yan Yan, was well-versed in Confucian classics and familiar with diagrams and predictions with Pei Xuanzheng from Hedong, Li Zhen from Longxi, Cai Jing, and others.