APA (7th ed.) Citation

Ek, J. A. v., & Trim, J. L. M. (1998). Threshold 1990 (Rev. and corr. ed.). University Press.

Chicago Style (17th ed.) Citation

Ek, Jan Ate van, and J. L. M. Trim. Threshold 1990. Rev. and corr. ed. Cambridge [etc.]: University Press, 1998.

MLA (9th ed.) Citation

Ek, Jan Ate van, and J. L. M. Trim. Threshold 1990. Rev. and corr. ed. University Press, 1998.