Graziano & Raulin
Research Methods (9th edition)
Preparing Appendices
The purpose of appendices is to provide material that would normally be distracting in the body of a text (e.g., a mathematical proof or the items of a scale that was developed). It can also be used to include something that is a product of the paper, but not a part of the paper itself, such as a psychological scale developed by the authors.
If there is only a single appendix, it should be labeled "Appendix." If there are several appendices, label them Appendix A, Appendix B, and so on.
The appendices should appear at the very end of the paper, and each should start on a separate page.