《资治通鉴·隋纪·隋纪四》
于是炀帝任命杨素为并州道行军总管、河北道安抚大使，率领几万军队讨伐杨谅。杨谅当初起兵时，他妃子的哥哥豆卢毓是汉王府主簿。
初，素将行，计日破贼，皆如所量，于是以素为并州道行军总管、河北道安抚大使，帅众数万以讨谅。
Then Emperor Yang appointed Yang Su as the commander in chief of the Bingzhou army and the pacification ambassador of Hebei, leading tens of thousands of troops to punish Yang Liang. When Yang Liang initially raised his army, his concubine's brother Doulu Yu was the chief staff of the Han Palace.