@techreport{NBERw2450,
 title = "What Do We Learn from Unit Roots in Macroeconomic Time Series?",
 author = "Danny Quah",
 institution = "National Bureau of Economic Research",
 type = "Working Paper",
 series = "Working Paper Series",
 number = "2450",
 year = "1987",
 month = "November",
 URL = "http://www.nber.org/papers/w2450",
 abstract = {It is often argued that the presence of a unit root in aggregate output implies that there is no "business cycle": the economy does not return to trend following a disturbance. This paper makes this notion precise, but then develops a simple aggregative model where this relation is contradicted. In the model output both has a unit root, and displays repeated short-run fluctuations around a deterministic trend. Some summary statistical evidence is presented that suggests the phenomena described in the paper is not without empirical basis.},
}