1. BELLLABS: The picture of the future. Bell Labs Rec. 47(5), 134–186 (1969)
2. RFC-958: Network Time Protocol (NTP). http://www.ntp.org/ . Accessed 28 Apr 2017
3. Cornell University: The CU-SeeMe Project. http://ftp.icm.edu.pl/packages/cu-seeme/html/Welcome.html . Accessed 28 Apr 2017
4. The Cambridge iTV Trial. http://koo.corpus.cam.ac.uk/projects/itv/ . Accessed 28 Apr 2017
5. Caltech/CERN Project. http://pcbunn.cithep.caltech.edu/ . Accessed 28 Apr 2017