APA

L.A.Alexander تاليف, .First Things First:Students Book. New York:Cambridge University Press,1989: .

Chicago

L.A.Alexander تاليف, .First Things First:Students Book. New York:Cambridge University Press,1989: .

Harvard

L.A.Alexander تاليف, .First Things First:Students Book. New York:Cambridge University Press,1989: .

MLA

L.A.Alexander تاليف, .New York:Cambridge University Press,1989: . .