> I think citing from an appendix of a PDF version is still fair use, as long as you make the source clear

I'd always assumed so. I've regularly cited Perl Best Practices (pdf) ... as I did only last month, while issuing dazz a yellow card for repeated whinging about Perl's unfortunate Switch statement. If that's not fair use, I apologize ... though I certainly don't relish having to edit all my old nodes. :)

I suppose Perlish alternatives to a Switch statement is yet another candidate topic for your course.