[Proj] Method of reference to license within software code modules

[Gerald I. Evenden]

Not a bash nor editorial.

Question: does/should a copy of the license that covers a program module be 
placed within each and every source file??

I had been putting a copy of the MIT in every file of whatever that ends up in 
a distubution tarball.  Is that necessary?  I doubt that a copy of the 10,000 
lines of GPL ends up in each of Stallman's files.  ;-)

Is a reference and url (such as 
http://www.opensource.org/licenses/mit-license.php
sufficient?

Anyway, I feel that I have been a bit excessive.

Thanks.

-- 
The whole religious complexion of the modern world is due
to the absence from Jerusalem of a lunatic asylum.
-- Havelock Ellis (1859-1939) British psychologist