https://www.socialeurope.eu/stability-or-stagnation-how-europes-fiscal-rules-are-strangling-growth
https://www.progressivepolicy.org/blogs/ppis-trade-fact-of-the-week-military-spending-was-2-3-of-world-gdp-last-year/
https://www.mckinsey.com/~/media/McKinsey/Business%20Functions/Organization/Our%20Insights/Decision%20making%20in%20uncertain%20times/Decision-making-in-uncertain-times.ashx
http://www.imf.org/external/np/seminars/eng/2015/secularstag/pdf/Venkateswaran.pdf