《新唐书·列传·卷五十一》
又准备赐牛仙客实封户，张九龄说 ：汉朝的法令，不是有功之人不封。唐遵汉法，是太宗定下的制度。
又欲赐实封，九龄曰： 汉法非有功不封，唐遵汉法，太宗之制也。
He was also prepared to bestow a fiefdom on Niu Xianke, but Zhang Jiuling said: "According to the laws of the Han Dynasty, only those who have made meritorious contributions should be enfeoffed. Tang followed the Han law, which was a system established by Emperor Taizong."