《魏书·列传·卷十》
二十二年冬，御史台令史龙文观因犯法判处死刑，上告廷尉，称说元恂以前被拘捕在京城附近时，有亲笔信自己申诉不知道谋反事情，而中尉李彪、侍御史买尚扣压不报告。
二十二年冬，御史台令史龙文观坐法当死，告廷尉，称恂前被摄左右之日，有手书自理不知状，而中尉李彪、侍御史贾尚寝不为闻。
In the winter of the twenty-second year, Office of the Imperial Censors Historiographer Long Wenguan was sentenced to death for breaking the law. Before his execution, he reported to the Court of Judicial Review that when Yuan Xun was arrested and detained in the outskirts of the capital, he sent a handwritten letter to the emperor saying that he was unaware of the rebellion plot, but palace attendant Li Biao and Palace Attendant Inspector Mai Shang hid the letter and refused to report it.