1. Foley, Duncan. 1986. Understanding Capital: Marx' Economic Theory. Boston, Massachusetts: Harvard University Press.
2. Marx, Karl. 1990 (1867). Capital, Vol. I. London: Penguin Classics.
3. - 1863. Theories of Surplus Value, Vol 1. www.marxists.org/archive/marx/ works/1863/theories-surplus-value
4. Productive and unproductive labor: a reply to Houston and Laibman
5. Moseley, Fred. 2003. "Marxian Crisis Theory and the Postwar US Economy." In Alfredo Saad-Filho, ed., Anti-Capitalism: A Marxist Introduction. London: Pluto Press. http://home.mtholyoke.edu/~fmoseley/