Lipsey, R. G. (1989). An introduction to positive economics (7th ed.). ELBS/ Weidenfeld & Nicholson.
Cita Chicago (17th ed.)Lipsey, Richard G. An Introduction to Positive Economics. 7th ed. London: ELBS/ Weidenfeld & Nicholson, 1989.
Cita MLA (9th ed.)Lipsey, Richard G. An Introduction to Positive Economics. 7th ed. ELBS/ Weidenfeld & Nicholson, 1989.
Atenció: Aquestes cites poden no estar 100% correctes.