《资治通鉴·隋纪·隋纪七》
柴孝和劝说李密： 秦地山川险固，秦、汉正是凭借着它建立帝王之业的。
柴孝和说李密曰： 秦地山川之固，秦、汉所凭以成王业者也。
Chái Xiàohé advised Lǐ Mì: "The geographical features of the Qin region are very rugged. Qin and Han both depended on it to establish their imperial enterprise."