《魏书·列传·卷十二》
等到昭成帝逝世，太祖将要迁往长安。
及昭成崩，太祖将迁长安。
Yan Feng, seeing that Emperor Taizu was young and weak, repeatedly asked Fu Jian, "The Dai lord just died, his subjects have started to desert and rebel, and his grandson is young and without ministers to support and protect him."