《资治通鉴·唐纪·唐纪十三》
当此时，众位大臣大都说道： 朝廷既然答应与他们通婚，又接受了人家的聘礼，就不可失信于薛延陀，以免又生边乱。 
是时，群臣多言： 国家既许其昏，受其聘币，不可失信戎狄，更生边患。 
At this time, many ministers said: “The Court has agreed to marry into the Xueyantuo clan and accepted their gifts, so we should not break our promise to the Xueyantuo, otherwise we might cause trouble on the border.”