APA

Bowler B., Cunningham S., . (1997). Headway. Upper-intermediate. Oxford: Oxford University Press.

Chicago

Bowler B, Cunningham S, . 1997. Headway. Upper-intermediate. Oxford: Oxford University Press.

Harvard

Bowler B., Cunningham S., . (1997). Headway. Upper-intermediate. Oxford: Oxford University Press.

MLA

Bowler B, Cunningham S, . Headway. Upper-intermediate. Oxford: Oxford University Press. 1997.