==================== HES POSTING ===================== I am not quite sure what you mean by original sources in this context. The earliest paper that I know in which Lucas contrasts the adaptive expectations version of the Phillips curve with the rational expectations version is "Econometric Testing of the Natural Rate Hypothesis" in a Board of Governors of the Federal Reserve System conference volume entitled The Econometrics of Price Determination. This is reprinted in Lucas's Studies in Business Cycle Theory and in Hoover (ed.) The New Classical Macroeconomics (Elgar), and possibly elsewhere. Earlier than that, you might find Lucas and Rappings papers in JPE 1969 and AER 1969 helpful. The history of the new classical approach to the Phillips curve is recounted in a number of places, including chapter 2 of my The New Classical Macroeconomics (Blackwell - rather confusingly titled the same as the Elgar anthology.) Kevin Hoover [log in to unmask] ============ FOOTER TO HES POSTING ============ For information, send the message "info HES" to [log in to unmask]