requirements for a GPL

Can I get some advice on what is required to claim a GPL for a package?

A package I maintain (pcurve) uses some S code from statlib.  I have an email 
from the author of the S code saying that he would be happy to issue a GPL 
for the code.  Is the email from the author enough, or do I need something 
more formal?

r-devel is not an ideal place to ask for this sort of advice, especially 
as the correct answer may be country-specific.  It's unlikely that many 
people on this list are experts in Australian IP law.

Formally, you almost certainly need the permission of the copyright 
holder, who may or may not be the author.  Assuming goodwill and no large 
sums of money at stake, permission from the author is probably pretty 
safe.  For example, the survival package was initially circulated with 
permission from the author, but now is GPL with permission from the Mayo 
Foundation for Medical Education and Research, who are the real copyright 
owners of Dr Therneau's code.


 	-thomas

Thomas Lumley			Assoc. Professor, Biostatistics
tlumley@u.washington.edu	University of Washington, Seattle