《资治通鉴·隋纪·隋纪三》
过了几天，有关部门的官员秉承杨素的意思，奏报文帝说元常常曲意迎逢杨勇，有阿谀结交之事。在仁寿宫，杨勇派他的亲信裴弘给元送信，信上写着 勿令人见 。
居数日，有司承素意，奏元旻常曲事于勇，情存附托，在仁寿宫，勇使所亲裴弘以书与旻，题云： 勿令人见 。
After a few days, officials of the relevant departments acted in accordance with Yang Su's intentions and reported to Emperor Wen that Yuan often flattered and fawned on Yang Yong and had colluded with him in flattery. At Renshou Palace, Yang Yong sent his confidant Pei Hong to send a message to Yuan, with the message "Don't show it to other people."