Nature 482, 485–488
The case for open computer programs
http://www.nature.com/nature/journal/v482/n7386/full/nature10836.html#/potential-barriers-and-proposed-solutions
Nature Editorial: If you want reproducible science, the software needs to be open source
http://arstechnica.com/science/news/2012/02/science-code-should-be-open-source-according-to-editorial.ars