This paper develops a procedure for uncovering the common cyclical factors that drive a mix of stationary and nonstationary variables. The method does not require knowing which variables are nonstationary or the nature of the nonstationarity. An application to the FRED-MD macroeconomic dataset...

"This paper reviews some of the literature on the macroeconomic effects of oil price shocks with a particular focus on possible nonlinearities in the relation and recent new results obtained by Kilian and Vigfusson (2009)"--National Bureau of Economic Research web site

"This paper surveys the history of the oil industry with a particular focus on the events associated with significant changes in the price of oil. Although oil was used much differently and was substantially less important economically in the nineteenth century than it is today, there are...