《三国志·魏书·方技传》
文帝曹丕看重柴玉，又曾经下令杜夔和左马真等人在宾客面前吹笙弹琴，杜夔面有难色，因此曹丕感到不悦。
文帝爱待玉，又尝令夔与〈马真〉等於宾客之中吹笙鼓琴，夔有难色，由是帝意不阅。
Emperor Wen Cao Pi valued Chai Yu and once ordered Du Kui and Zuo Ma Zhen to play the sheng and qin in front of the guests. Du Kui looked troubled, and Cao Pi was displeased.