《文心雕龙·乐府》
不但传说天上常奏《万舞》，而且上古葛天氏的时候也曾有过八首乐歌。
钧天九奏，既其上帝；葛天八阕，爰及皇时。
Not only does legend say that "Wandance" is often played in heaven, but in the days of Ge Tianshi in ancient times, there were also eight pieces of music.