The history of Bagua Zhanghttp://realtaoism.blogspot.co.uk/2012/05/short-history-of-reality-of-ba-gua.html
My teacher, Chris Chappellhttp://youtu.be/4p8xZMDGjP4
 
The Bagua Master, Frank Allenhttp://www.wutangpca.com/frank-allen.html