《三国志·魏书·武文世王公传》
太和六年，又进封号为怀王，追谥曹赞为西乡哀侯。
六年，又进号曰怀王，追谥赞曰西乡哀侯。
In the sixth year of Taihe Emperor, he was further honoured with the title Huai Wang, and posthumously honoured Cao Zan was honoured with the title Xixiang Ai Hou.