Hardwick, P., & Langmead, J. a. K. B. (1999). An introduction to modern economics (5th ed.). Prentice hall.
Cita Chicago (17th ed.)Hardwick, Philip, i John and Khan Bhadur Langmead. An Introduction to Modern Economics. 5th ed. Harlow, England: Prentice hall, 1999.
Cita MLA (9th ed.)Hardwick, Philip, i John and Khan Bhadur Langmead. An Introduction to Modern Economics. 5th ed. Prentice hall, 1999.
Atenció: Aquestes cites poden no estar 100% correctes.