《论衡·卷二十八·正说篇》
解释《易》的人都认为是伏羲制作了八卦，周文王把它推演为六十四卦。
说《易》者皆谓伏羲作八卦，文王演为六十四。
The people who interpret the Book of Changes all believe that Fu Xi created the Eight Trigrams, and King Wen of Zhou extrapolated them into the sixty-four hexagrams.