《资治通鉴·晋纪·晋纪二十三》
拓跋什冀犍性格宽容厚道，郎中令许谦盗窃了两匹绢丝，拓跋什冀犍知道后就加以隐瞒，还对左长史燕凤说： 我不忍心看到许谦，如果见面后许谦因惭愧而自杀，这就是我因财货而杀手下的官吏了。 
什翼犍性宽厚，郎中令许谦盗绢二匹，什翼犍知而匿之，谓左长史燕凤曰： 吾不忍视谦之面，卿慎勿泄。若谦惭而自杀，是吾以财杀士也。 
Tuoba Shiyijian was tolerant and righteous in character. When the Minister of the Imperial Clan, Xu Qian, stole two bolts of silk, Tuoba Shiyijian found out but covered it up and said to the Left Grand Chronicler Yan Feng: I cannot bear to look upon Xu Qian, and if I meet with him, he will certainly commit suicide out of shame. Thereby I will have killed one of my officials on account of goods. 