《后汉书·列传·逸民列传》
建武末年，沛王刘辅等五王住在北宫，都好宾客，再次派人请井丹，不能请来。
建武末，沛王辅等五王居北宫，皆好宾客，更遣请丹，不能致。
At the end of the Jianwu reign, the five kings including Liu Fu, the King of Pei, lived in the North Palace. They were all fond of guests and sent someone to invite Jing Dan again, but they failed.