What legal principle refers to a contractor being referred to other documents not contained in the provided documents?

The correct answer is based on the principle of "Incorporated by Reference." This legal principle allows for certain documents that are not physically included within a contract to still be considered as part of that contract when they are explicitly referenced. By using this principle, a contractor can incorporate additional documents, such as compliance manuals, specifications, or other relevant agreements, without needing to attach every single document directly to the main contract.

For instance, if a contract states that it is subject to the terms outlined in a separate document and explicitly names that document, then the content of the named document is legally binding as part of the contract, even though it wasn't physically included in the pages of the primary contract itself. This is particularly useful in construction and contracting practices, where multiple technical documents are often involved.

The other options, while potentially related to contract terminology, do not accurately capture this specific legal concept. "Legal Reference" is too vague and does not denote a specific principle relating to contracts. "Terms of Agreement" refers to the agreed-upon conditions within a contract, but does not encompass the idea of including other documents. "External Documentation Clause" might sound relevant but does not specifically define a recognized legal principle in contract law as "Incorporated by Reference"