These issues of GX, Guard Experience have a couple of articles on Guard SF...
http://www.1800goguard.com/downloads/magazine/GX55Book.pdf
http://www.1800goguard.com/downloads/magazine/gx5_6_Book.pdf
http://www.1800goguard.com/downloads/magazine/GX55Book.pdf
http://www.1800goguard.com/downloads/magazine/gx5_6_Book.pdf