^Gregory and Stuart, Paul and Robert. The Global Economy and its Economic Systems. South-Western College Pub. 2013-02-28: 30. ISBN 978-1285055350. Economic system – A set of institutions for decision making and for the implementation of decisions concerning production, income, and consumption within a given geographic area.
^Samuelson, P. Anthony., Samuelson, W. (1980). Economics. 11th ed. / New York: McGraw-Hill. p. 34
^David W. Conklin (1991), Comparative Economic Systems, University of Calgary Press, p.1.
^Rosser, Mariana V. and J Barkley Jr. Comparative Economics in a Transforming World Economy. MIT Press. 2003-07-23: 8. ISBN 978-0262182348. This leads us to describe two extreme categories: market capitalism and command socialism. But this simple dichotomization raises the possibility of “cross forms,”, namely, market socialism and command capitalism. Although less common than the previous two, both have existed.
^Rosser, Mariana V. and J Barkley Jr. Comparative Economics in a Transforming World Economy. MIT Press. 2003-07-23: 8. ISBN 978-0262182348. Indeed, aside from the variation of ownership forms, some follow certain ideas in Marx, saying that how one class relates to another is the crucial matter rather than specifically who owns what, with true socialism involving a lack of exploitation of one class by another. This kind of argument can lead to the position that the Soviet Union was not really socialist but a form of state capitalism in which the government leaders exploited the workers.