Lipsey, R. G., & Chrystal, K. A. (1999). Principles of economics (9th ed.). Oxford University Press.
Lua i Stíl Chicago (17ú heag.)Lipsey, Richard G., agus K. Alec Chrystal. Principles of Economics. 9th ed. Oxford ; New York: Oxford University Press, 1999.
Lua MLA (8ú heag.)Lipsey, Richard G., agus K. Alec Chrystal. Principles of Economics. 9th ed. Oxford University Press, 1999.
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