APA (7th ed.) Citation

Gale Group & Free, R. C. (2010). 21st century economics: A reference handbook. SAGE.

Chicago Style (17th ed.) Citation

Gale Group and Rhona C. Free. 21st Century Economics: A Reference Handbook. Thousand Oaks, Calif: SAGE, 2010.

MLA (9th ed.) Citation

Gale Group and Rhona C. Free. 21st Century Economics: A Reference Handbook. SAGE, 2010.