D. Abrams, R. Baecker, and M. Chignell. Proceedings of the SIGCHI Conference on Human Factors in Computing Systems, page 41--48. New York, NY, USA, ACM Press/Addison-Wesley Publishing Co., (1998)
C. Cattuto, D. Benz, A. Hotho, and G. Stumme. Proceedings of the 7th International Conference on The Semantic Web, 5318, page 615--631. Springer-Verlag, (2008)
E. Chi, and T. Mytkowicz. HT '08: Proceedings of the nineteenth ACM conference on Hypertext and hypermedia, page 81--88. New York, NY, USA, ACM, (2008)