A nice table show the difference between difference type of opensource licence

http://www.petefreitag.com/item/533.cfm
http://blogs.zdnet.com/Burnette/?p=131
http://www.codinghorror.com/blog/archives/000833.html
http://onlamp.com/lpt/a/5330

A more detail look of GPL: http://blogs.zdnet.com/BTL/?p=2463&part=rss&tag=feed&subj=zdblog

Summary of some key point of typical business licence - http://www.codinghorror.com/blog/archives/000892.html

Free book about it - http://www.oreilly.com/catalog/osfreesoft/toc.html

Another discussion about choosing open source licence using - http://blog.jooq.org/2014/03/31/open-source-completely-underestimates-contributor-license-agreements/

Cost of GPL - http://bitsplitting.org/2016/10/30/the-price-of-gpl/
