
https://www.ifs.org.uk/uploads/publications/bns/BN243.pdf

https://www.brookings.edu/blog/techtank/2021/07/10/the-biden-administration-takes-an-overdue-first-step-to-foster-competition/?utm_campaign=Brookings%20Brief&utm_medium=email&utm_content=140224222&utm_source=hs_email

https://www.brookings.edu/blog/up-front/2018/07/12/as-trump-twists-natos-arm-lets-run-the-math-on-defense-spending/?utm_campaign=Brookings%20Brief&utm_source=hs_email&utm_medium=email&utm_content=64421876