1. Additional Protocol to the Council of Europe Convention on the Prevention of Terrorism, https://www.coe.int/en/web/conventions/full-list/-/conventions/treaty/217.
2. Angelovski I., Marzouk L., Patrucic M., Making a Killing: The 1.2 Billion Euro Arms Pipeline to Middle East, Balkan Insight, 27.07.2016, https://balkaninsight.com/2016/07/27/making-a-killing-the-1-2-billion-euros-arms-pipeline-to-middle-east-07-26-2016/.
3. Barret R., Beyond The Caliphate: Foreign Fighters and the Threat of Returnees, “The Soufan Center”, October 2017, https://thesoufancenter.org/wp-content/uploads/2017/11/Beyond-the-Caliphate-Foreign-Fighters-and-the-Threat-of-Returnees-TSC-Report-October-2017-v3.pdf.
4. Begisholli B., Kosovo Detains More Returnees From Syrian Battlefields, Balkan Insight, 24.04.2019, https://balkaninsight.com/2019/04/24/kosovo-detains-more-returnees-from-syrian-battlefields/.
5. Beslin J., Ignjatijevic M., Balkan foreign fighters: from Syria to Ukraine, “Brief ISSUE”, 2017, no. 20.