《宋书·志·卷十五》
博士傅郁议论说： 《礼记》里记载，微子舍弃他的嫡孙不立而立弟弟衍为继嗣，商朝的制度因此而施行。
博士傅郁议： 《礼记》，微子立衍，商礼斯行。
Doctor Fu Yu said in his discussion: The Ritual Records records that Weizi did not establish his legitimate grandson but established his younger brother Yan as successor, which is how the Shang Dynasty’s system was implemented.