《宋书·志·卷十一》
令太乐郎刘秀、邓昱等人依照音律制作笛子，三尺二寸与无射律相应，如果要用长的笛子，管理奏乐的人说： 请奏无射之乐。 
部郎刘秀、邓昊等以律作笛，三尺二寸者，应无射之律，若宜用长笛，执乐者曰： 请奏无射。 
Emperor Taile ordered musicians Liu Xiu and Deng Yu to make bamboo flutes according to the musical notes: three foot and two inches would correspond to the note 'Wu She'. If one wanted to play a longer flute, the music director would say: "Please play the music of 'Wu She'."