GFDL licensed books better for Wikibooks or Wikisource? (or nowhere?)

I just discovered <http://www.indiana.edu/%7Ehlw/index.html> How
Language Works (edition 3.0) by Michael Gasser. It's GFDL.

I guess if it was at Wikisource it would be in a more archivey way,
whereas at Wikibooks you would hope people would continue to develop
it... is that about right?

cheers
Brianna

-- 
They've just been waiting in a mountain for the right moment:
http://modernthings.org/