《新五代史·列传·死事传第二十一》
况且张源德虽然仗恃刘郡的军队，但和沧州互为首尾，如今德州在中间而没有防备，不如先攻占德州，那么沧、贝二州的势力被分开就容易谋取了。 
且源德虽恃刘鄩之兵，然与沧州相首尾，今德州居其中而无备，不如先取之，则沧、贝之势分而易图也。 
Moreover, although Zhang Yuande relies on Liu Jun's army, he and Cangzhou are closely related. Now Dezhou is in the middle but not prepared. It is better to capture Dezhou first. Then it will be easy to seize the power of the other two states, Cang and Bei.