《宋书·志·卷十七》
国没有继位嗣王，由三卿主祭。是否与有丧服之例相同? 
博士颜僧道议： 《礼记》云： 所祭者亡服则不祭。 
The two countries did not have a successor king, so the three ministers led the sacrificial rite. Is this in accordance with the precedent of mourning?