how to incorporate derived work from Maxima into an open-source library?

Hi,

thanks to the great help from this mailing list
the technical problem of how to cope with those
annotations is solved. Alas, there is the legal
side :-(

Now I have these code snippets, mainly minor
modifications of existing Maxima code.
And I want to release them with my library,
the OKlibrary (see http://www.ok-sat-library.org/).
Since Maxima is released under the GPL (version x ?),
I assume that there is no principal problem.

(Actually, I just had a look at http://maxima.sourceforge.net/authorization-letter.html,
and aren't the mentioned restrictions not incompatible with the GPL?
Doesn't the GPL require unrestricted redistribution, for all human
beings, even if from other countries? So well, let's ignore this
here ...)

So I assume I can add these code snippets to my library, under
the appropriate GPL version x, which is?

My library is under the GPLv3, which I regard as essential, since
it contains a lot of research, and I really don't want to see
that patented by somebody else.
I believe there shouldn't be a problem with these code excerpts
under GPLvx, but what is the opinion about releasing it
under GPLv3?

And then there is the question about the copyright.
As far as I know, the copyright is only relevant w.r.t.
changing the licence. Whom shall I mention in the
copyright notice?

Yet the new file with that redefined load-function
is part of my main library. However I could also
package it as part of the Maxima distribution (which
I redistribute) --- perhaps this is less troublesome?

I hope once we clarify these issues here, then we can
treat future cases similarly.

Thanks!

Oliver