Ek, J. A. v., & Trim, J. L. M. (1984). Across the threshold: Readings from the modern languages projects of the Council of Europe. Pergamon Press.

Ek, J. A. van, and J. L. M. Trim. Across the Threshold: Readings from the Modern Languages Projects of the Council of Europe. Oxford: Pergamon Press, 1984.

Ek, J. A. van, and J. L. M. Trim. Across the Threshold: Readings from the Modern Languages Projects of the Council of Europe. Pergamon Press, 1984.