Tagarev, Todor, Raphael Perl, and Valeri Ratchev. "Recommendations and Courses of Action: How to Secure the Post-Covid Future." In Transatlantic Security: Securing the Post Covid Future, 18-41. Vienna, Austria: Federal Ministry of Defense, 2020.

Perl, Raphael, and Nemanja Malisevic. "A Comprehensive Approach to Cyber Security ?Trends,  Challenges and the Way Forward." In The Dangerous Landscape, 47-61., 2013.

Perl, Raphael. "Enhancing Diplomatic Effectiveness: A Common-Sense Risk Management Approach to Counter-terrorism." Connections: The Quarterly Journal 8, no. 4 (2009): 99-107.

Perl, Raphael. "Combating Extremist Ideologies: Measuring Effectiveness-Considerations for Public Diplomacy." Connections: The Quarterly Journal 5, no. 4 (2006): 64-72.

Perl, Raphael. Terrorism and National Security: Issues and Trends. Washington, D.C.: Congressional Research Service, 2006.

Perl, Raphael. Combating Terrorism: The Challenge of Measuring Effectiveness. Washington, D.C.: Congressional Research Service, 2005.