Ciro Cattuto Giancarlo Ruffo Filippo Menczer HYPERTEXT 2009, Proceedings of the 20th ACM Conference on Hypertext and Hypermedia, Torino, Italy, June 29 - July 1, 2009 ACM 2009 db/conf/ht/ht2009.html 978-1-60558-486-7 Hypertext