Farooq, Umer, Kannampallil, Thomas G., Song, Yang, Ganoe, Craig H., Carroll, John M., Giles, Lee: Evaluating tagging behavior in social bookmarking systems: metrics and design heuristics. In: GROUP '07: Proceedings of the 2007 international ACM conference on Conference on supporting group work. New York, NY, USA : ACM, 2007. - ISBN 978-1-59593-845-9, S. 351--360
Farooq, Umer, Song, Yang, Carroll, John M., Giles, C. Lee, Social Bookmarking for Scholarly Digital Libraries, in: IEEE Internet Computing 11 6 (2007), S. 29--35.