《旧五代史·后唐·列传二十二》
李严说 ：我国把契丹看作跳蚤虱子一般，因它没多大伤害，用不着抓搔。
严曰： 吾国视契丹如蚤虱耳，以其无害，不足爬搔。
Li Yan said: Our country regards the Khitan as fleas and lice, because they don't do much harm, so there is no need to scratch them.