1. https://www.modernhealthcare.com/cybersecurity/hackers-taking-advantage-covid-19-spread-malware
2. https://www.statista.com/statistics/991304/worldwide-cybersecurity-spending/
3. M. Singh, I. Mukhopadhyay, Cyber Security Issues in the COVID-19 Times. Lecture Notes on Data Engineering and Communications Technologies 62, 671–680 (2021)
4. Kim Crawley, Cybersecurity budgets explained: how much do companies spend on cybersecurity? May 2020
5. Michael Castellucio, 2020 Major Hacks and Syber Espionage. January 13, 2021