《魏书·列传·卷九十一》
世宗不答复使者，让朝廷有关官员下诏书给勿六跋说： 蠕蠕的远祖社仑是大魏国的叛臣，我们对过去的事予以宽容，暂时与你通使往来。
世宗不报其使，诏有司敕勿六跋曰： 蠕蠕远祖社仑是大魏叛臣，往者包容，暂时通使。
Emperor Shizong did not answer the envoy, and instructed the relevant officials to issue an edict to Wuliubaba, saying: "The distant ancestor of the Rouran, Shelun, was a traitor of the Great Wei Kingdom. We have tolerated the past, and temporarily communicate with you as an envoy.