APA (7th ed.) Zitazioa

TREGIDGO, P. Practical English usage for overseas: Students (2nd ed.). Longman.

Chicago Style (17th ed.) Zitazioa

TREGIDGO, P.S. Practical English Usage for Overseas: Students. 2nd ed. London: Longman.

MLA (9th ed.) Zitazioa

TREGIDGO, P.S. Practical English Usage for Overseas: Students. 2nd ed. Longman.