how should I cite a publication where the author(s) are anonymous (but the organization is not)

I'd like to cite the following articles from the Nature Publishing Group, but no authors are mentioned (as far as I can tell):

1. http://ift.tt/1Cfv5m7


2. http://ift.tt/1FOMMNs

However, it's likely that it was written by one (or more) of Nature's editors. If, for example, I am using the BibTeX formatting system, how should I describe the author of the article? For example:

1. author={Nature} 2. author={Nature Publishing Group} 3. author={anonymous} 4. author={}

Or should I leave it blank (option 4)?