At least once I have cited an excellent online resource for studying the Wudang styles of swordsmanship. The resource is Paul Brennan’s translation of Essentials of the Wudang Sword Art by Huang Yuanxiu, published in 1931 by Commercial Press.
Brennan’s online translation includes some excerpts of original calligraphy as well as the original illustrative photographs. The information is fairly technical, but if you have worked your way through an elementary course of study, possibly with Scott Rodell’s Chinese Swordsmanship or Zhang Yun’s Art of Chinese Swordsmanship, you can make the connections to the content of this text. The full text of Brennan’s translation of Essentials of Wudang Sword Art by Huang Yuanxiu can be accessed HERE.