Guell, R. C., & Robert C. Guell. (2010). Issues in economics today. Boston: McGraw-Hill/Irwin.
Chicago Style aipamenaGuell, Robert C., và Robert C. Guell. Issues in Economics Today. Boston: McGraw-Hill/Irwin, 2010.
MLA aipamenaGuell, Robert C., và Robert C. Guell. Issues in Economics Today. Boston: McGraw-Hill/Irwin, 2010.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.