1. ISO/IEC 2382:2015, Information technology — Vocabulary, Clause 01.01.40: Defines a standard as a "document, established by consensus and approved by a recognized body, that provides, for common and repeated use, rules, guidelines or characteristics for activities or their results..." This definition implies the establishment of a norm for "common and repeated use."
2. Naik, K., & Tripathy, P. (2008). Software Testing and Quality Assurance: Theory and Practice. Wiley. Chapter 2, Section 2.4, "Quality Standards": This section explains that standards like ISO and CMMI provide a framework of best practices that are expected to be followed by organizations to achieve a certain level of quality. This establishes them as the expected norm for process implementation.
3. Pressman, R. S., & Maxim, B. R. (2019). Software Engineering: A Practitioner's Approach (9th ed.). McGraw-Hill Education. Chapter 16, "Software Quality Assurance": The text discusses how SQA activities are governed by a set of standards. It states, "A quality management system can be defined as the organizational structure, responsibilities, procedures, processes, and resources for implementing quality management." These procedures and processes, defined by standards, become the organizational norm.