Robert H. Perry's 2022 Contract Security Industry White Paper
Security Advisor Newsetter Winter 2022
Security Letter: 2021 List of Largest Guard Companies in the U.S.
Security Advisor Newsletter Summer 2021
U.S. Department of Labor/Bureau of Labor Statistics:
2021 Employment and Wage Data for Security Guards
2021 Occupational Outlook Handbook - Security Guards
Security Letter: 2020 List of Largest Guard Companies in U.S.
Security Letter: 2019 List of Largest Guard Companies in U.S.