APA استشهاد

Lipsey, R. G. (1963). introduction to positive economics (3rd ed.). English Language Book Society.

استشهاد بنمط شيكاغو

Lipsey, Richard G. Introduction to Positive Economics. 3rd ed. London: English Language Book Society, 1963.

MLA استشهاد

Lipsey, Richard G. Introduction to Positive Economics. 3rd ed. English Language Book Society, 1963.