S. Maslov, and S. Redner. (2009)cite arxiv:0901.2640
Comment: 3 pages, 1 figure, invited comment for the Journal of Neuroscience.
The arxiv version is microscopically different from the published version.
K. Chen, R. Lu, C. Wong, G. Sun, L. Heck, and B. Tseng. CIKM '08: Proceeding of the 17th ACM conference on Information and knowledge management, page 1143--1152. New York, NY, USA, ACM, (2008)