Ritter, F. E., Baxter, G. D., & Churchill, E. F. Foundations for desgning user-centered systems: What system designers need to know about people.
Chicago-viite (17. p.)Ritter, Frank E., Gordon D. Baxter, ja Elizabeth F. Churchill. Foundations for Desgning User-centered Systems: What System Designers Need to Know About People.
MLA-viite (8. p.)Ritter, Frank E., et al. Foundations for Desgning User-centered Systems: What System Designers Need to Know About People.
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