《太平广记·卷八十八·异僧二》
襄国护城河的水源，在城西北五里处，水源突然枯竭了，石勒问澄用什么方法弄到水，澄说： 如今应当让龙取水。 
襄国城堑水源，在城西北五里，其水源暴竭。勒问澄： 何以致水？ 澄曰： 今当敕龙取水。 
The source of Xiangguo's moat was five li northwest of the city. The water source suddenly dried up. Shi Le asked Cheng what method he could use to get water. Cheng said: "Now we should let the dragon fetch water."