Hi Caleb,
The best way to learn FOSI is with my FOSI QuickStart Tutorials, which are available at my website at http://fosiexpert.com/products.html. The document files used in the tutorials are XML files, but I would be happy to make them SGML files for you. Also, excerpts from my book, Practical FOSI, are at http://fosiexpert.com/Practical-fosi.html.
Note that FOSI is an SGML application. A FOSI stylesheet consists of SGML elements and attributes that adhere to the OutSpec DTD. When you learn FOSI, you are also learning something about SGML :-)
In addition, there are books available about SGML.
Hope this helps! Please let me know any questions you may have.
Good luck!
Suzanne Napoleon
www.FOSIexpert.com
"WYSIWYG is last-century technology!"