Xian () occurs in the Chunqiu Fanlu, Fengsu Tongyi, Qian fu lun, Fayan, and Shenjian; xian () occurs in the Caizhong langji, Fengsu Tongyi, Guanzi, and Shenjian.
The concept of Xian () is mentioned in various texts such as the Chunqiu Fanlu, Fengsu Tongyi, Qian fu lun, Fayan, and Shenjian; similarly, xian () is referenced in Caizhong langji, Fengsu Tongyi, Guanzi, and Shenjian.