Börner, Katy, Klavans, Richard, Patek, Michael, Zoss, Angela M., Biberstine, Joseph R., Light, Robert P., Larivière, Vincent and Boyack, Kevin W.. "Design and Update of a Classification System: The UCSD Map of Science." PLoS ONE 7 , no. 7 (2012): e39464.
La Rowe, Gavin, Ambre, Sumeet, Burgoon, John, Ke, Weimao and Börner, Katy. "The Scholarly Database and its utility for scientometrics research." Scientometrics 79 , no. 2 (2009): 219--234.