Our approach in Principles is to lay a foundation with text discussion, using specific legal authorities to illustrate the principles discussed, their application, and exceptions. These authorities include GAO decisions and opinions, judicial decisions, statutory provisions, and other relevant sources. We would encourage users to start with at least a brief review of Chapter 1, which provides a general framework and context for all that follows. Chapter 1 includes a note regarding citations to GAO case law and other relevant GAO material and an explanation of those other materials.