《资治通鉴·唐纪·唐纪四》
封德对皇上说： 王世充得到的地方虽然多，但都不过是略有联系的部属，实际号令所能管辖的只不过洛阳一城而已，他已经智尽力穷，克城之日就在近期之内。
德彝言于上曰： 世充得地虽多，率皆羁属，号令所行，唯洛阳一城而已，智尽力穷，克在朝夕。
Fang De stated to the emperor that although Wang Shichong has occupied many places, most are detached and combined in name only, and that the only place under his actual control is Luoyang. Wang Shichong has run out of ideas and is at the end of his rope, and the date that our city will be conquered is near.