《贞观政要·卷四·教戒太子诸王》
从前汉武帝驾崩了以后，昭帝继位，燕王旦向来自高自大，不愿服人。霍光辅佐昭帝以御书诛杀了他，身亡国灭。
或汉武帝既崩，昭帝嗣立，燕王旦素骄纵，诪张不服，霍光遣一折简诛之，则身死国除。
In the past, after Emperor Wu of the Han Dynasty passed away, Emperor Zhao succeeded to the throne. King Dan of Yan has always been arrogant and unwilling to submit to others. Huo Guang assisted Emperor Zhao to kill him with imperial edict, and he died and the country was destroyed.