《水经注·卷十七》
这里有五城相连接，北城中有湖水，湖中曾出现过白龙，随着就是一阵风雨，所以汉武帝元鼎三年，把它改名为天水郡。
五城相接，北城中有湖水，有白龙出是湖，风雨随之，故汉武帝元鼎三年，改为天水郡。
Five cities are connected here, north of which is lake water. A white dragon had appeared in the lake, followed by a storm, so Emperor Wu of Han changed its name to Tianshui County in the third year of Yuanding.