《新唐书·列传·卷一百四十七》
乐工十二人，穿南诏服装，立在《辟四门》舞筵四角，指挥跪拜合拍合乐。
工十二人，服南诏服，立《壁四门》舞筵四隅，节拜合乐。
Twelve musicians wearing the costume of Nanzhao stand at the four corners of the platform on which the dance “Si Men” is performed. They are responsible for marshalling the dancers’ kneeling and prostrating, and for keeping the singing and the music in time.