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2. Marx, K., & Engels, F. (1972). Marx & Engels Selected Works, Volume 2: Marx: A Contribution to the Critique of Political Economy. Beijing: People’s Publishing House, pp. 82–83.
3. Marx, K., & Engels, F. (1979). Marx & Engels Collected Works, Volume 42: Marx: Economic and Philosophical Manuscripts of 1844. Beijing: People’s Publishing House, p. 121.
4. Marx, K., & Engels, F. (1995). Marx & Engels Selected Works, Volume 3: Marx & Engels: Socialism: Utopian and Scientific. Beijing: People’s Publishing House, p. 760.
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