I'm wondering how we reconcile situations like
http://en.wikibooks.org/wiki/Uim and
http://en.wikibooks.org/wiki/Scratch/Content_License
These are GFDL plus PD and CC-by-sa respectively. But we have no indication
whatsoever that contributors to the book (except Swift and Rob respectively)
have agreed to this arrangement. Unless there is some compelling argument
here, I'm of the view that the non-GFDL bit needs to be removed ASAP.
Contributors to Wikibooks may of course license their own contributions (in
whole or in part) under anything they want in addition to the GFDL (so
Swift's and Rob's contributions to those books may remain PD and CC-by-sa
respectively) but derivatives of their work on Wikibooks are GFDL-only
unless otherwise stated.
I really have to wonder who thought there was not a problem with this
situation - Swift apparently asked around and got an affirmative; I'm
surprised with Rob as well.
I should say this goes for any and all other books which are ostensibly
"dual-licensed" so if you find others, those arrangements should go on the
chopping block as well.
Mike