APA aipamena

(1981). World English: Workbook. Washington, DC.: United states Department of state.

Chicago Style aipamena

World English: Workbook. Washington, DC.: United states Department of state, 1981.

MLA aipamena

World English: Workbook. Washington, DC.: United states Department of state, 1981.

Kontuz: berrikusi erreferentzia hauek erabili aurretik.