In the 文始真經 'Wen Shi Zhen Jing' aka the "關尹子" "Guan Yin Zi", written in nine chapters; ~ Chinese text- http://ctext.org/wenshi-zhenjing & http://zh.wikisource.org/wiki/%E9%97%9C%E5%B0%B9%E5%AD%90
"The Wenshi zhenjing does not appear until the Yuan dynasty, when it is mentioned in Chen Zhensun's Zhizhai shuluyjieti , dated to 1240. It was probably compiled by the Quanzhen patriarch Yin Zhiping (1169-1251), an alleged descendant of Guan Yin. Before that time, in the twelfth and thirteenth centuries, remnants of an older text are mentioned in various Song bibliographies, but they have not survived."
