Ruffin, R., & Gregory, P. R. (1993). Principles of microeconomics (5th ed.). HarperCollins College Publishers.
Citazione stile Chigago Style (17a edizione)Ruffin, Roy, e Paul R. Gregory. Principles of Microeconomics. 5th ed. New York, NY: HarperCollins College Publishers, 1993.
Citatione MLA (9a ed.)Ruffin, Roy, e Paul R. Gregory. Principles of Microeconomics. 5th ed. HarperCollins College Publishers, 1993.
Attenzione: Queste citazioni potrebbero non essere precise al 100%.