For the second graded literature review please read the following two pieces each of which discusses the differences between the terms free software and open source software.
The first is Christin Peterson's How I coined the term 'open source' (archive)
The second is Benjamin Mako Hill's When Free Software Isn't Better (archive)
You can discuss the articles separately, or try to relate them to each other (eg, to compare or contrast them), at your discretion.
Please make a blog post with the litreview criteria in mind.