《宋书·志·卷十一》
二尺八寸四分四厘与黄钟律相对应，如果要用短的笛子，管理奏乐的人就可说： 请奏黄钟。 
二尺八寸四分四厘应黄钟之律，若宜用短笛，执乐者曰： 请奏黄钟。 
Two foot, eight inches, and four point four centimeters corresponds to the note 'Huang Zhong'. If one wanted to play a shorter flute, the music director could say: "Please play the music of 'Huang Zhong'."