I don't see any evidence the linked article is actually Open Access. It seems possible that the response just had the wrong link, and they article they are cha

I don't see any evidence the linked article is actually Open Access. It seems possible that the response just had the wrong link, and they article they are charging for isn't open access. http://www.sciencedirect.com/science/article/pii/S0168900210008910 http://www.sciencedirect.com/science/article/pii/S0168900210... is clearly Open Access, has a clear mark of that, and has full text available for free.