Cita APA (7th ed.)

Spencer, D. E., & Parkin, M. (1990). Study guide: Parkin : Economics. Addison-Wesley.

Cita Chicago (17th ed.)

Spencer, David E., i Michael Parkin. Study Guide: Parkin : Economics. Reading, Mass: Addison-Wesley, 1990.

Cita MLA (9th ed.)

Spencer, David E., i Michael Parkin. Study Guide: Parkin : Economics. Addison-Wesley, 1990.