《黄帝内经·灵枢·阴阳二十五人》
岐伯说：首先明确木、火、土、金、水五种类型的人，然后按照五色的不同加以区别，就容易知道二十五种人的形态了。
岐伯曰：先立五形，金木水火土，别其五色，异其五形之人，而二十五人具矣。
<translation>Qi Bo said: "First make clear the five types of people: wood, fire, earth, gold, and water, then distinguish them according to the different colors, it is easy to know the morphology of the 25 types of people.