Please use these sources:
https://www.fbi.gov/news/testimony/global-terrorism-threats-to-the-homeland-103019
https://www.csis.org/analysis/real-world-capabilities-isis-threat-continues
Chapter 21 of Global terrorism by James and Brenda Lutz
The routledge handbook of Terrorism Research by ALex P.Schmid, ALbert Jongman and Eric Price “The definition of terrorism”
The strategy of terrorism: how it works and why it fails chapter 2 pp12-30
https://www.fbi.gov/news/testimony/global-terrorism-threats-to-the-homeland-103019
