^McConnell, Campbell; Brue, Stanley; Flynn, Sean (2009). Economics. Boston: Twayne Publishers. p. G-22. ISBN978-0073375694.
^Gregory and Stuart, Paul and Robert (2013). The Global Economy and its Economic Systems. South-Western College Pub. p. 30. ISBN978-1285055350. There are three broad forms of property ownership – private, public, and collective (cooperative).
^Zimbalist, Andrew; Sherman, Howard J.; Brown, Stuart (October 1988). Comparing Economic Systems: A Political-Economic Approach. Harcourt College Pub. pp. 6–7. ISBN978-0-15-512403-5. Pure capitalism is defined as a system wherein all of the means of production (physical capital) are privately owned and run by the capitalist class for a profit, while most other people are workers who work for a salary or wage (and who do not own the capital or the product).
^Bertrand Badie; Dirk Berg-Schlosser; Leonardo Morlino (2011). International Encyclopedia of Political Science. Sage Publications. p. 2132. ISBN978-1412959636. Private property cannot exist without a political system that defines its existence, its use, and the conditions of its exchange. That is, private property is defined and exists only because of politics.