《魏书·列传·卷二十三》
况且蠕蠕依仗它地处极其辽远，以为国家的力量达不到，自我宽慰由来已久，所以夏季就分散部众放牧牲畜，秋季马肥又聚集，背朝寒冷面向温暖，南下抢掠。
且蠕蠕恃其绝远，谓国家力不能至，自宽来久，故夏则散众放畜，秋肥乃聚，背寒向温，南来寇抄。
Besides, the Rourans rely on the extreme remoteness of their territory, and take comfort in the fact that the power of the state cannot reach far. Thus, in the summer, they disperse their people to graze their livestock, and in the autumn when their horses are fat, they gather together again, turning their backs to the cold and facing the warmth, going south to plunder.