《北齐书·列传·卷四十五》
造无非是改变风俗造成的，都变成了亡国之音；可是同样为了应付习俗的变化，表现形式却不相同，什么原因呢?
莫非易俗所致，并为亡国之音；而应变不殊，感物或异，何哉？
 Transformation is nothing other than the results of changes in customs, which have all been transformed into music that brings ruin to states; however, to respond to the same changes in customs, the forms of expression are different, what is the reason for this?