Article ($32): http://www.nature.com/nature/journal/vaop/ncurrent/full/natu...
Preprint: http://arxiv.org/abs/1205.3909
Preprint: http://arxiv.org/abs/1205.3909
"we believe the publisher adds relatively little value to the publishing process... We are simply observing that if the process really were as complex, costly and value-added as the publishers protest that it is, 40% margins wouldn't be available."[0]
[0]: http://en.wikipedia.org/wiki/Academic_publishingIn any case, just read the preprint instead. It's basically the same.