Fortunately, neither appear to be behind the paywall. In fact, it appears that the original article is free, as well: http://www.nature.com/nature/journal/vnfv/

Fortunately, neither appear to be behind the paywall. In fact, it appears that the original article is free, as well: http://www.nature.com/nature/journal/vnfv/ncurrent/pdf/nature09042.pdf http://www.nature.com/nature/journal/vnfv/ncurrent/pdf/natur...