TREGIDGO, P. Practical English usage for overseas: Students (2nd ed.). Longman.
Citazione stile Chigago Style (17a edizione)TREGIDGO, P.S. Practical English Usage for Overseas: Students. 2nd ed. London: Longman.
Citatione MLA (9a ed.)TREGIDGO, P.S. Practical English Usage for Overseas: Students. 2nd ed. Longman.
Attenzione: Queste citazioni potrebbero non essere precise al 100%.