I have selected the document below as reference for my research into yin-yang theory, eight trigrams and Yi Jing to support theories concerning Nejia, Taijiquan, Baguaquan, Bamen Wubu (Eight Gates and Five Steps), Shisan Shi (Thirteen Postures), with regard to the Xiantian and Houtian Bagua (Eight Trigrams) circular arrangement.
This annotated version of the this document can also be found via Bradford Hatcher's (the author's) web page