1. National Institute of Standards and Technology (NIST) Special Publication 800-64 Rev. 2
Security Considerations in the System Development Life Cycle.
Section 2.2
Development / Acquisition Phase (Page 8): "During this phase
the system is developed or acquired
installed
and configured in accordance with the specifications detailed in the design phase... System documentation is developed during this phase... Training materials are also developed and finalized during this phase." This directly aligns the activities of development (programming)
documentation
and training within a single phase.
2. Purdue University
College of Technology Courseware
CNIT 45500 - Systems and Software Security.
Module: Secure Software Development Life Cycle
"Implementation Phase": Course materials describe this phase as where the actual code is written based on the design documents. It also emphasizes the creation of secure coding standards and initial documentation for the system's functionality
which precedes formal user training.
3. Sommerville
I. (2016). Software Engineering (10th ed.). Pearson.
Chapter 2
Section 2.1.3
"Software design and implementation": This academic textbook describes the implementation stage as the process of "realizing the design as a program." It is distinct from the design phase (creating specifications) and the validation phase (testing). The development of user documentation is also cited as a key activity during implementation.