《资治通鉴·唐纪·唐纪三》
窦建德又与王世充联合交好，派遣使节进表于皇泰主，黄泰主封他为夏王。
又与王世充结好，遣使奉表于隋皇泰主，皇泰主封为夏王。
Dou Jiande and Wang Shichong became friends and allies. He sent an emissary to pay tribute to Emperor Huatei, and Emperor Huatei conferred upon him the title of King of Xia.