PAPELL, DAVID H; PRODAN, RUXANDRA - In: Economic Inquiry 45 (2007) 4, pp. 834-853
"In a classic paper, Nelson and Plosser could not reject the unit root hypothesis in favor of trend stationarity for 13 out of 14 long-term annual macro series. Subsequent studies, allowing for one or two structural changes, have found more rejections with a broken trend stationary alternative....