1. Agutter, C. (2020). ITIL 4 essentials: Your essential guide for the ITIL 4 foundation exam and beyond. IT Governance Ltd.
2. Anderson, S. (2011). Seductive interaction design: Creating playful, fun, and effective user experiences. New Riders.
3. Chisholm, W., & May, M. (2008). Universal design for Web applications: Web applications that reach everyone. O'Reilly Media.
4. Downe, L. (2020). Good services: How to design services that work. BIS.
5. Eichler, F. (1973). Geschäftsbericht 1972/73 der Braun AG