[1] http://www.gnu.org/licenses/gpl.html [2] http://archives.cnn.com/2000/TECH/computing/03/28/cyberpatrol.mirrors/ [3] Open Source: the Unauthorized White Papers, Donald K. Rosenberg, IDG Books, 2000. Quotes are from page 114, ``Effects of the GNU GPL''. [4] In the "What License to Use?" section of http://www.oreilly.com/catalog/opensources/book/brian.html This whitepaper is a condensation of an original work available at http://alumni.cse.ucsc.edu/~brucem/open_source_license.htm