《太平广记·卷三百一十八·鬼三》
在并州当祭酒的桓回，在刘聪当皇帝的建元三年时在道上遇见一个老人，向他打听说：有个乐师叫成凭，现在任什么职？
并州祭酒桓回，以刘聪建元三年，于途遇一老父。问之云：有乐工成凭，今何职？
Huan Hui, was a Sacrificial Official in Bingzhou. During the third year of the Jian Yuan period, when Liu Cong was emperor, he met an old man on the road. He asked the old man: Is there a musician called Cheng Ping? What position does he currently hold?