1. International standard ISO/IEC 25010:2011. (2011), "Systems and software engineering - Systems and software Quality Requirements and Evaluation (SQuaRE) - System and software quality models", International Organization for Standardization, International Electrotechnical Commission, Institute of Electrical and Electronics Engineers.
2. International standard ISO/IEC 9126-1:2001. (2001), "Software engineering - Product quality. Part 1: Quality model", International Organization for Standardization, International Electrotechnical Commission. Institute of Electrical and Electronics Engineers.
3. International standard ISO 9241-11:2018. (2018), "Ergonomics of human-system interaction - Part 11: Usability: Definitions and concepts", International Organization for Standardization, International Electrotechnical Commission, Institute of Electrical and Electronics Engineers.
4. International standard ISO/IEC 14764:2006. (2006), "Software Engineering - Software Life Cycle Processes - Maintenance", International Organization for Standardization, International Electrotechnical Commission, Institute of Electrical and Electronics Engineers.
5. Seffah, A., Donyaee, M., Kline, R. B. and Padda, H. K. (2006), "Usability measurement and metrics: A consolidated model", Software Quality Journal, V 14, no. 2, pp. 159-178. DOI: http://doi.org/10.1007/s11219-006-7600-8