1. How voice and video call works?
https://blog.mindorks.com/how-voice-and-video-call-works-b0896aa0a630
2. Ranked: The world’s most downloaded apps - visual capitalist.
https://www.visualcapitalist.com/ranked-most-downloaded-apps/
3. Statistics on cyber-terrorism.
http://csciwww.etsu.edu/gotterbarn/stdntppr/stats.htm
4. Wireshark.
https://www.wireshark.org/
5. Cyberbullying facts and statistics for 2016–2019 (2019).
https://www.comparitech.com/internet-providers/cyberbullying-statistics