1. K. Marx, Grundrisse, in K. Marx and F. Engels, Marx-Engels Gesamtausgabe (Berlin: Dietz Verlag, 1976), Abt. II, Band 1.1, p. 36.
2. H. Williams, Hegel, Heraclitus and Marx’s Dialectic (Hemel Hempstead: Harvester Wheatsheaf, 1989), pp. 69
3. Tony Smith, The Logic of Marx’s ‘Capital’ (Albany, NY: SUNY Press, 1990).
4. K. Marx, Capital, Vol. I, Collected Works, 35 (London: Lawrence & Wishart, 1996), p. 19.
5. G. W. F. Hegel, The Encyclopaedia Logic, tr. T. F. Garaets et al. (Indianapolis: Hackett, 1991)