《资治通鉴·汉纪·汉纪十八》
于是引起归附汉朝的各羌人部落和归义羌侯杨玉的愤怒怨恨，不再信任、顺服汉朝，于是劫掠弱小种族，侵犯汉朝边塞，攻打城池，杀伤官吏。
于是诸降羌及归义羌侯杨玉等怨怒，无所信乡，遂劫略小种，背畔犯塞，攻城邑，杀长吏。
This aroused the anger and resentment of the Qiang tribes and the Guiyi Qiang Hou Yang Yu who had surrendered to the Han, and they no longer trusted or obeyed the Han, so they plundered weak races, invaded the Han border, attacked cities, and killed officials.