《资治通鉴·唐纪·唐纪三十》
王悔到了可突干的牙帐，觉察到契丹上下并没有真心降附的意思，只不过是把军营稍往西北移了一些，并秘密地派人去联兵突厥，阴谋杀掉王悔而反叛。于是王悔知道可突干是诈降。
悔至其牙帐，察契丹上下初无降意，但稍徙营帐近西北，密遣人引突厥，谋杀悔以叛；悔知之。
When Wang Hui arrived at Ke Tudan's headquarters, he ascertained that the Khitan rulers did not really want to surrender, but had only moved their barracks slightly to the northwest and secretly sent men to make an alliance with the Turks, plotting to kill Wang Hui and rebel. Thus, Wang Hui realized that Ke Tudan's surrender was a sham.