APA استشهاد

Lipsey, R. G. (1971). An introduction to positive economics. ELBS.

استشهاد بنمط شيكاغو

Lipsey, Richard G. An Introduction to Positive Economics. London: ELBS, 1971.

MLA استشهاد

Lipsey, Richard G. An Introduction to Positive Economics. ELBS, 1971.