Cita APA (7a ed.)

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

Cita Chicago Style (17a ed.)

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

Cita MLA (9a ed.)

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