1. ACTFL. (2012).ACTFL proficiency guidelines.https://www.actfl.org/publications/guidelines-and-manuals/actfl-proficiency-guidelines-2012
2. ACTFL. (2016).Assigning CEFR ratings to ACTFL assessments.https://www.actfl.org/resources/assigning-cefr-ratings-actfl-assessments
3. Die Grenzen des Sagbaren;Adler, H. G;Muttersprache,1965
4. Cultural studies and the canon: Some thoughts on Stefan George;Berman R. A.;Profession,1999