> 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.