Bollen's Clickstream Map of Science

Bollen, Johan, Herbert Van de Sompel, Aric Hagberg, Bettencourt Luı́s M.A., Ryan Chute, Marko A. Rodriguez, and Lyudmila Balakireva. “Clickstream Data Yields High-Resolution Maps of Science.” PLoS ONE 4, no. 3 (March 2009): e4803. doi:10.1371/journal.pone.0004803.