Barzel, Baruch
Barabási, Albert-László
Article History
First Online: 7 April 2015
Change Date: 30 April 2015
Change Type: Erratum
Change Details: In the version of this article initially published, citations were given for Supplementary Software 1 and 2; these files have been removed from the website and the citations replaced by ones for figshare and GitHub (see supplementary information for explanation). The Software files have been available on figshare since publication and are now also available at GitHub (ExternalRef removed), the link for which we have added to the paper. The changes have been made in the HTML and PDF versions of the article.
Competing interests
: The authors declare no competing financial interests.