1. Adams, R. J., Wu, M. L., & Wilson, M. R. (2015). ACER ConQuest: Generalised item response modelling software [Computer software]. Version 4. Camberwell, Victoria: Australian Council for Educational Research.
2. Autorengruppe Bildungsberichterstattung. (2018). Bildung in Deutschland 2018: Ein indikatorengestützter Bericht mit einer Analyse zu Wirkungen und Erträgen von Bildung [Education in Germany 2018: An indicator-based report including an analysis of the effects and yields of education]. Retrieved from https://www.bildungsbericht.de/de/bildungsberichte-seit-2006/bildungsbericht-2018/pdf-bildungsbericht-2018/bildungsbericht-2018.pdf.
3. The language demands of school. Putting academic English to the test,2007
4. Encyclopedia of bilingualism and bilingual education;Baker,1998
5. Bilingual effects on cognitive and linguistic development: Role of language, cultural background, and education;Barac;Child Development,2012