《黄帝内经·灵枢·岁露论》
这是什么原因造成的呢？少师说：这需要在交立八节的时候，观察四正、四隅气候是否异常。
少师曰：此八正之候也。
What is the cause of this? The lesser tutor said: This necessitates observing whether the climate of the four cardinal and four corner points is abnormal at the eight junctures between seasons.