APA

Bowler B., Cunningham S., . (1992). Headway upper-intermediate pronunciation. New York: Osford University Press.

Chicago

Bowler Bill, Cunningham Sarah, . 1992. Headway upper-intermediate pronunciation. New York: Osford University Press.

Harvard

Bowler B., Cunningham S., . (1992). Headway upper-intermediate pronunciation. New York: Osford University Press.

MLA

Bowler Bill, Cunningham Sarah, . Headway upper-intermediate pronunciation. New York: Osford University Press. 1992.