《汉书·传·楚元王传》
太上皇为他说话，高祖说： 某不敢忘了封他，是因为他母亲不慈厚。 
太上皇以为言，高祖曰： 某非敢忘封之也，为其母不长者。 
The retired emperor spoke for him, and the founding emperor said, "I do not dare forget to enfeoff him, for his mother is not gracious and gentle."