《汉书·传·赵充国辛庆忌传》
酒泉太守辛武贤上奏书说道： 各郡的兵力都驻守在祁连山南，北边空虚，这种形势一定不会坚持太久。
酒泉太守辛武贤奏言： 郡兵皆屯备南出，北边空虚，势不可久。
Xin Wuxian, the governor of Jiuquan, wrote a memorial saying: The troops of all counties are stationed in the south of Qilian Mountains, and the north is empty. This situation will certainly not last long.