《旧唐书·列传·卷一百三十五》
允济便揭开牛主人蒙头的衣衫，对他妻子娘家人说： 这就是你女婿，你可以把牛还给他。 
允济遂发蒙，谓妻家人曰： 此即女婿，可以牛归之。 
Yunji then uncovered the dam owner's head and said to his wife's family, "This is your son-in-law. You can return the dam to him now."