《宋书·志·卷十二》
邹衍是周代人，不可能不知道周代与哪一行相应，而且周代的历法有八百年，秦就是在周代建国的，周代符合火德还是木德的问题是容易搞清楚的。
衍生在周时，不容不知周氏行运。且周之为历年八百，秦氏即有周之建国也。周之火木，其事易详。
Zou Yan was Zhou Dynasty people, it was impossible for him not to know which element Zhou Dynasty corresponded to, and Zhou Dynasty's calendar had been used for eight hundred years. Qin was established during Zhou Dynasty, so it was easy to clarify whether Zhou Dynasty complied with fire element or wood element.