Here is the paper they cite:
http://papers.ssrn.com/sol3/papers.cfm?abstract_id=1502864
One of the authors of the research paper has a lot of work on innovation and open source in general:
One of the authors of the research paper has a lot of work on innovation and open source in general:
Thanks for the link to the author's site. He has a non SSRN link to the paper on the following page; the link text is the "(PDF)" that follows the SSRN link he first cites.