《水经注·卷十四》
《春秋》记载：襄公四年前，无终子嘉父派孟乐出使晋国，通过魏绛献上虎豹皮，请求晋侯与戎族各部议和。
《春秋》襄公四年，无终子嘉父使孟乐如晋，因魏绛纳虎豹之皮，请和诸戎是也，故燕地矣。
The <Spring and Autumn Annals> records: Four years before Duke Xiang's reign, Wuzhong Zi Jiafu sent Meng Le to visit the state of Jin through Wei Jiang to offer tiger and leopard skins, and to request the Duke of Jin to negotiate a peace agreement with various tribes of the Rong people.