| Conceptualizing state counterterrorism O Lewis The Palgrave handbook of global counterterrorism policy, 3-37, 2017 | 23 | 2017 |
| Security Cooperation between Western States: Openness, Security and Autonomy O Lewis Routledge, 2023 | 4 | 2023 |
| Conceptualizing Counterterrorism O Lewis Insurgency and Counterinsurgency in Modern War, 1-16, 2016 | 4 | 2016 |
| Trilemma Tradeoffs in International Relations: An Analytical Framework O Lewis Global Studies Quarterly 4 (1), 2024 | | 2024 |
| Small state influence in EU security policy-making: PESCO, Frontex and the integration dilemma B Dominici, O Lewis, S Steingass Small States in EU Policy-Making: Strategies, Challenges, Opportunities, 143-158, 2024 | | 2024 |
| Conceptualizing non-state counter-terrorism O Lewis Counter-terrorism and civil society, 32-46, 2021 | | 2021 |
| Explaining military, law enforcement and intelligence cooperation between Western states ORTD Lewis University of St Andrews, 2018 | | 2018 |
