1. Barnier, M. (2018). Speech by Michel Barnier at the EU Institute for Security Studies conference. Retrieved February 28, 2022, from https://ec.europa.eu/commission/presscorner/detail/en/SPEECH_18_3785
2. Besch, S. (2016). Waging war on the myth of an EU army. Politico. Retrieved January 9, 2022, from https://www.politico.eu/article/waging-war-on-the-myth-of-an-eu-army-referendum-britain-brexit-debate/
3. Biscop, S. (2016). All or nothing? The EU Global Strategy and defence policy after the Brexit. Contemporary Security Policy, 37(3), 431–445.
4. Biscop, S. (2017). Differentiated integration in defence: A plea for PESCO. EU60: Re-founding Europe. The responsibility to propose. Istituto Affari Internazionali. Retrieved January 3, 2022, from https://www.iai.it/en/pubblicazioni/differentiated-integration-defence-plea-pesco
5. Biscop, S. (2021). Kill the Battlegroups. Egmont. Retrieved January 18, 2022, from https://www.egmontinstitute.be/kill-the-battlegroups/