APA

van Ek J. A., Trim J. L. M., . (1998). Waystage 1990. Cambridge: Cambridge University Press.

Chicago

van Ek J A, Trim J L M, . 1998. Waystage 1990. Cambridge: Cambridge University Press.

Harvard

van Ek J. A., Trim J. L. M., . (1998). Waystage 1990. Cambridge: Cambridge University Press.

MLA

van Ek J A, Trim J L M, . Waystage 1990. Cambridge: Cambridge University Press. 1998.