Shalamanov, Velizar, Pavel Anastasov, and Georgi Tsvetkov. "Deterrence and Defense at the Eastern Flank of NATO and the EU: Readiness and Interoperability in the Context of Forward Presence." Connections: The Quarterly Journal 18, no. 1 (2019): 25-42.

Prezelj, Iztok, and Marija Gaber. Smuggling as a Threat to National and International Security: Slovenia and the Balkan Route In Athena Papers. Vol. 5. Garmisch-Partenkirchen: Partnership for Peace Consortium of Defense Academies and Security Studies Institutes, 2005.