[1] The term “freedom fighter” has been coined in 1850 by Karl Heinzen, author of “Murder and Liberty.” – Cf. Daniel Bessner and Michael Stauch (2010): “Karl Heinzen and the Intellectual Origins of Modern Terror,” Terrorism and Political Violence, Vol. 22, no. 2, pp. 143-176. This article contains an English translation of Heinzen’s ‘Mord und Freiheit’. The dictum “one man’s terrorist is the other man’s freedom fighter” confuses ends and means. The ends of an act of violence might be legitimate (like in the case of national self-defense) but the means of the same act of violence might not be, e.g when those attacked are unarmed civilians not responsible for the conflict in which they have become victims. The same relates to war: a just war, when fought by unjust means, loses (some of its) legitimacy

[2] Phillips, Brian J. (2014): “What is a terrorist group? Conceptual issues and empirical implications.” Terrorism and Political Violence 27 (February): pp. 225-242.

[3] James Forest has rightly pointed out, that “…terrorism is a product of characteristics and conditions combined with interactions between individual choices, organisational choices, and the environmental dimensions that influence those choices” – James J.F. Forest. Terrorism as a Product of Choices and Perceptions. Westpoint, N.Y.: Combating Terrorism Center, 2009, p. 31.

[4] Cf. Astrid Bötticher (2017): Radikalismus und Extremismus. Konzeptualisierung und Differenzierung zweier umstrittener Begriffe in der deutschen Diskussion. The Hague: Leiden University, doctoral dissertation. Bötticher noted: ‘The historical roots of radicalism lie in the (self-)description of liberal and republican movements, while the historical roots of extremism can be found in the external labelling of ideology-driven violent movements’. - A. Bötticher. Proposition no. 2 pertaining to Ph.D. Dissertation defense on 24 May 2017). - Extremism has recently been defined by John M. Berger as“….the belief that an in-group’s success or survival can never be separated from the need for hostile action against an out-group. The hostile action can range from verbal attacks and diminishment to discriminatory behaviour, violence, and even genocide”. - J.M. Berger (2018): Extremism. Cambridge, Mass.: M.I.T. Press, p.44

[5] The term “terrorists” was reportedly coined by Gracchus Babeuf, a French journalist and egalitarian agitator, who himself later became a victim of the guillotine. - Barry Rubin and Judith C. Rubin (2008): Chronologies of Modern Terrorism. Armonk, N.Y.: M.E. Sharpe, p. 7.

[6] Levitt, Geoffrey (1986): “Is Terrorism Worth Defining?” Ohio Northern University Law Review 13, pp. 97-116

[7] Ben Saul (2006): Defining Terrorism in International Law. Oxford: Oxford University Press, pp. 48-49 and p.214.

[8] M. G. Marshall and T. R. Gurr. Peace and Conflict. College Park, University of Maryland, Center for International Development & Conflict Management, 2005, p. 63

[9]  Alex P. Schmid (1984): Political Terrorism. A Research Guide to Concepts, Theories, Data Bases and Literature. With a Bibliography by the Author and a World Directory of “Terrorist” Organizations by A.J. Jongman. Amsterdam: North-Holland Publishing Company, pp.76-77

[10] Carol Winkler, In the Name of Terrorism: Presidents on Political Violence in the Post- World War II Era, Albany, NY, State University of New York Press, 2006, pp. 11-16.

[11] Peter C. Sederberg (1989): Terrorist Myths: Illusion, Rhetoric, and Reality. Englewood Cliffs, New Jersey: Prentice Hall, p.3.

[12] 8 B. Seddon and A. Malaret Baldo, Counter-IED Capability Maturity Model & Self-Assessment Tool, UNIDIR, 2020 (in particular, pp. 10–15).