Hi,
Could someone provide me with an english abstract of the issues ?
In europe the only issue I've found has to do with the "moral" right to withdraw a work from distribution. And even in that case, nobody was able to answer me on what happens to derived works on such an event.
For France, at least two legal research papers about the GPL concluding to its validity (both in French):
http://soufron.free.fr/files/recherche.html http://crao.net/gpl/
As always with lawyers, there isn't unanimity on this subject.