1. Economist.Com
https://www.economist.com/finance-and-economics/2008/12/30/diagnosing-depression
2. National Bureau of Economic Research
https://www.nber.org/news/business-cycle-dating-committee-announcement-june-8-2020
3. Where Is There Consensus Among American Economic Historians? The Results of a Survey on Forty Propositions
4. Black Tuesday: The Stock Market Crash of 1929;Feinberg,1995
5. Black gold: The end of Bretton Woods and the oil-price shocks of the 1970s;Hammes;Indep. Rev.,2005