《水经注·卷十三》
正如《诗经》所描写的：赤膊徒手把猛虎捉住，把它进献于公的住处。因此魏时有《捍虎图》。水又流经平城西侧城内，此城为魏泰常七年所建。
敕虎士效力于其下，事同奔戎，生制猛兽，即《诗》所谓袒裼暴虎，献于公所也。故魏有《捍虎图》也。又径平城西郭内，魏太常七年所城也。
As described in the "Book of Songs": hunting tigers bare-handed and giving them to the Duke. Therefore, there was a "Tiger Defense Picture" at that time. The water then flows through the west side of Pingcheng City, The city was built in the seventh year of Wei Taichang.