ii This identification strategy has been proposed by O. J. Blanchard and D. Quah, “The Dynamic Effects of Aggregate Demand and Supply Disturbances,” The American Economic Review 79, no. 4 (1989): 655–673. Demand shocks are neutral for GDP in the long run, while supply shocks have permanent effects on GDP in the long run.
Ben S Bernanke: Developments in the financial markets Testimony of Mr Ben S Bernanke, Chairman of the Board of Governors of the US Federal Reserve System, before the Committee on Banking, Housing, and Urban Affairs, US Senate, Washington DC, 3 April 2008.