It is pretty standard advice that relevant references to other documents should be listed in a separate section of the procedure. The reasoning is that when some standard operating procedures are intimately linked to others – the information contained in more than one document is necessary to complete a task – it is useful to include a cross-reference section in each document. Many also say that this section reinforces the SOP’s authority.
Another fairly common piece of advice is to have this, or another, section in the procedure identify the documents used in the development of the procedure, such as regulatory documents or technical/validation reports.
My take is that neither belongs in a process/procedure (SOP/WI). We should be looking to streamline requirements documents, and these sections are just cruft.
If you have electronic document control systems then cross-references should be handled trough hyperlink. Users are quite comfortable with hyperlinks and will easily navigate between documents.
Listing of regulations and other requirements belongs in a separate design document (ideally part of the document control system), and again add little value to the execution of the document.
There are a lot of so-called “best practices” about documents that stem from the days where everything is paper, and it is okay to move beyond them.