Παραπομπή APA

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

Παραπομπή Chicago Style

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

Παραπομπή MLA

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

Πρόσοχή: Οι παραπομπές μπορεί να μην είναι 100% ακριβείς.