《新唐书·列传·卷四十九》
姚崇答道 ：知古是我引荐的，我儿子必定以为知古看重我对他有恩，因而向他有所请托。 
对曰： 知古，臣所荐也，臣子必谓其见德而请之。 
Yao Chong replied, “Zhigu was recommended by me. My sons must think that Zhigu values me and is grateful for my kindness, so they went to him for help.