1. A. Aftalion, “Les Trois Notions de la Productitite et Revenus,”Revue d'Economie Politique, 1911.
2. W. Brown, “An Economic Application of Catastrophe Theory,” unpublished doctoral dissertation, Colorado University, 1977.
3. J. M. Clark, “Business Acceleration and the Law of Demand,”Journal of Political Economy, March 1917 pp. 217–35.
4. J. M. Keynes,The General Theory of Employment, Interest, and Money, New York: Harcourt, Brace and World, 1936.
5. A. Leijonhufvud,On Keynesian Economics and the Economics of Keynes, New York: Oxford University Press, 1968.