《资治通鉴·唐纪·唐纪三十五》
再说睢阳如果被叛军攻占，下一个就是临淮，此二城犹如毛皮相依，怎么能够见死不救呢！ 
且睢阳既拔，即及临淮，譬如皮毛相依，安得不救！ 
Furthermore, if Suiyang were to be conquered by the rebel army, the next city would be Linhuai. These two cities are as interdependent as fur and skin, so how can we just stand by and watch them perish?