added resource for understanding open source licenses (#2034)

free-programming-books.md

@@ -365,6 +365,7 @@
 #### Licensing
 
 * [Creative Commons: a user guide](http://www.aliprandi.org/cc-user-guide/) - Simone Aliprandi
+* [Open Source Licensing Software Freedom and Intellectual Property Law](http://rosenlaw.com/oslbook/) - Lawrence Rosen
 * [The Public Domain: Enclosing the Commons of the Mind](http://www.thepublicdomain.org/download/) - James Boyle