APA

SOARS J., SOARS L., . (1992). Headway upper-intermediate. Oxford: Oxford University Press.

Chicago

SOARS John, SOARS Liz, . 1992. Headway upper-intermediate. Oxford: Oxford University Press.

Harvard

SOARS J., SOARS L., . (1992). Headway upper-intermediate. Oxford: Oxford University Press.

MLA

SOARS John, SOARS Liz, . Headway upper-intermediate. Oxford: Oxford University Press. 1992.