Cita APA (7th ed.)

Sharp, A. M., Register, C. A., & Leftwich, R. H. (1990). Economics of social issues (9th ed.). BPI/IRWIN.

Cita Chicago (17th ed.)

Sharp, Ansel M., Charles A. Register, i Richard H. Leftwich. Economics of Social Issues. 9th ed. Homewood, IL: BPI/IRWIN, 1990.

Cita MLA (9th ed.)

Sharp, Ansel M., et al. Economics of Social Issues. 9th ed. BPI/IRWIN, 1990.