Stephen G. Hall, Zacharias Psaradakis, and Martin Sola, "Detecting Periodically Collapsing Bubbles: A Markov-Switching Unit Root Test", Journal of Applied Econometrics, Vol. 14, No. 2, 1999, pp. 143-154. The ASCII file hps.dat contains Argentinian monthly data on the logarithm of: (1) exchange rate (in terms of the US Dollar); (2) monetary base; (3) consumer price index. All series are from 1983:M1 to 1989:M12. Data are organised by variable.