1. Apple: iOS human interface guidelines. https://developer.apple.com/library/ios/documentation/UserExperience/Conceptual/MobileHIG/
2. Committee of e-government guideline: usability survey of e-government, 20 April 2009. https://www.kantei.go.jp/jp/singi/it2/guide/kaisai_h20/dai2/sankousiryou2.pdf
3. Hartson, R., Pyla, P.S.: The UX Book: Process and Guidelines for Ensuring a Quality User Experience. Morgan Kaufmann, San Francisco (2012)
4. ISO 9241-110: Ergonomics of human-system interaction – Part 110: Dialogue principles. ISO (2006)
5. ISO 9241-210: Ergonomics of human-system interaction – Part 210: Human-centred design for interactive systems. ISO (2010)