《太平广记·卷三十·神仙三十》
不一会儿，有一头白兽来到，他让杨德祖骑上去。白兽走得很快，渐渐觉得更远了，就问离长安多远了。凡八兄说： 这已经八万里啦！ 
八兄长笑一声，逡巡，有白兽至焉，命德祖乘之，其行迅疾，渐觉弥远。因问长安里数。八兄曰： 此八万里矣。 
Soon afterwards, a white beast arrived, and he asked Yang Dezu to ride it. The white beast walked very fast, They gradually felt further away, So he asked how far it was from Chang'an. Brother Fan Ba said: This is already eighty thousand li away!