《周书·列传·卷三十三》
杨荐到了蠕蠕族，责备他们忘恩失信，并谈论结为婚姻的意向。
荐至蠕蠕，责其背惠食言，并论结婚之意。
Yang Jian went to the Rouran and criticized them for forgetting their gratitude and betraying their promise, and talked about the intention of forming a marriage alliance.