What the C-test is. Lucy Katona and Zoltan Dornyei. From: Forum English Teaching. Posted on Effortless English Archives, 2004.
The C-Test bibliography. Rüdiger Grotjahn. 2011.
Der C-Test: Theoretische Grundlagen und praktische Anwendungen, Band 4. (abstracts and some chapters are in English) Rüdiger Grotjahn, ed. AKS-Verlag. Contributors include Dr. Ashley J. Hastings of Global Language Education Services.
University language learning and the C-Test. James Coleman, Rüdiger Grotjahn and Ulrich Raatz, eds. 2002. AKS-Verlag.
A cloze-up on the C-Test: a study in the construct validation of authentic tests. Christine Klein-Braley. Language Testing June 1985 vol. 2 no. 1 76-104.