1. Aff, J., & Lindner, J. (2005). Entrepreneurship education zwischen “small and big ideas” – Markierungen einer Entrepreneurship Education an wirtschaftsberuflichen Vollzeitschulen [Entrepreneurship education between “small and big ideas” – marks of entrepreneurship education at full-time business schools]. In Aff, J., & Hahn, A. (Eds.), Entrepreneurship-Erziehung und Begabungsförderung an wirtschaftsberuflichen Vollzeitschulen [Entrepreneurship education and talent promotion at full-time business schools] (pp. 83–138). Innsbruck: StudienVerlag.
2. Bortz, J., & Döring, N. (2016). Forschungsmethoden und Evaluation in den Sozialund Humanwissenschaften [Research methods and evaluation in the social and human sciences]. Berlin/Heidelberg: Springer.
3. European Commission. (2005). Recommendations of the European Parliament and the Council on key competences for life-long learning. Brussels: KOM 548. Retrieved from https://eur-lex.europa.eu/legal-content/EN/TXT/HTML/?uri=LEGISSUM:c11090&from=EN
4. European Commission. (2018). Council Recommendation of 22 May 2018 on key competences for lifelong learning. Official Journal of the European Union, 189, 1. Retrieved from https://eur-lex.europa.eu/legalcontent/EN/TXT/HTML/?uri=OJ:C:2018:189:FULL&from=EN
5. Fredrickson, B. (2009). Positivity: Top-notch research reveals the 3-to-1 ratio that will change your life. New York: Three Rivers Press.