《汉书·传·杨胡朱梅云传》
所以周武王减商，未下车，就存五帝之后，封殷后于宋，封夏后于杞，着明为三统相继，表示不独占天下。
故武王克殷，未下车，存五帝之后，封殷于宋，绍夏于杞，明著三统，示不独有也。
Therefore, when King Wu of Zhou reduced Shang, before he got off the chariot, he preserved the descendants of the Five Emperors, enfeoffed the Yin descendants in Song, and enfeoffed the Xia descendants in Qi. He made it clear that the three lines of succession were in succession, indicating that he did not monopolize the world.