《汉书·传·赵充国辛庆忌传》
皇上知道这件事后，就征询赵充国，赵充国答道： 羌入之所以容易被制，是因为他们各部落都有自己的首领，他们经常互相攻击，势力不能统一。
上闻之，以问充国，对曰： 羌人所以易制者，以其种自有豪，数相攻击，势不一也。
After the emperor heard about this, he consulted with Zhao Chongguo, and Zhao Chongguo said, "The reason the Qiang people can be easily controlled is that each of their tribes has its own leader, and they attack each other frequently, so their powers cannot be united."