《资治通鉴·隋纪·隋纪二》
虞庆则班师途中，走到潭州临桂崐岭，观察眺望山川形势，说道： 此地确实地形险要，如果有充足的粮草，再委派得力干将据险防守，攻不可破。 
庆则还，至潭州临桂岭，观眺山川形势，曰： 此诚险固，加以足粮，若守得其人，攻不可拔。 
On his way back to the capital, Yu Qingze went to Tanguan Lingui Qunling, where he observed the terrain of the mountains and water and said, "This place is very dangerous. If there is sufficient food and grass, and capable generals are sent to defend it, it will be impossible to attack."