A. Dattolo, F. Ferrara, and C. Tasso. Proc. of the 3rd International Conference on Human System Interaction - HSI'2010, page 548-555. Rzeszow, Poland, IEEE press, (May 2010)
C. man Au Yeung, N. Gibbins, and N. Shadbolt. HT '09: Proceedings of the Twentieth ACM Conference on Hypertext and Hypermedia, New York, NY, USA, ACM, (July 2009)