《资治通鉴·汉纪·汉纪六十》
及至关羽进攻樊城，吕蒙向孙权上书说： 关羽征讨樊城，却留下很多军队防守，一定是害怕我从后面进攻他。
及羽攻樊，吕蒙上疏曰： 羽讨樊而多留备兵，必恐蒙图其后故也。
When Guan Yu attacked Fancheng, Lu Meng wrote to Sun Quan and said, "Guan Yu is attacking Fancheng, but he has left many troops behind to defend it. He must be afraid that I will attack him from behind."