[1] https://googleblog.blogspot.ca/2009/06/lets-make-web-faster.html

[2] BONDI, André B. Foundations of Software and System Performance Engineering: Process, Performance Modeling, Requirements, Testing, Scalability, and Practice. Upper Saddle River, NJ: Addison-Wesley, 2015.

[3] MEIER, J. D. et al. Performance Testing Guidance for Web Applications. Redmond, WA: Microsoft Corporation, 2007.

[4] https://www.smashingmagazine.com/2015/11/why-performance-matters-part-2-perception-management/

[5] https://speakerd.s3.amazonaws.com/presentations/2ece664392024e9da39ea82e3d9f1139/perception-performance-ux-confoo-3-4.pdf