1. Adriason L, Hjelmquist E (1991) Group processes in face-to-face and computer-mediated communication. Behav Inf Technol 10(4):281–294
2. Aggarwal A (ed) (2003) Web-based learning and teaching technologies: opportunities and challenges. Idea Group Publishing, Hershey
3. Agosti M, Albrechtsen H, Ferro N, Fromholtz I, Hansen P, Orio N, Panizzi E, Pejtersen AM, Thiel U (2005a) DiLAS: a digital library annotation service. In: Boujut J-F (ed) International workshop on annotation for collaboration. Methods, tools and practices, Paris, 24–25 November 2005, pp 91–101
4. Agosti M, Ferro N, Albrechtsen H, Fromholtz I, Panizzi E, Thiel U (2005b) Design, implementation and evaluation of the use of digital multimedia annotations in DL interaction and DL users collaboration. In: Thanos C (ed) DELOS research activities 2005, Gruppo ALI Pisa, Italy, pp 47–48
5. Andronico A, Chianese A, Ladini B (2002) E-Learning: metodi, strumenti ed esperienze a confronto. Liguori Editore, Napoli, Italia