Scientific discoveries are an iterative process, influencing and building off of each other. The Reference section of an article lists the material that provided the authors with ideas, comparisons, or methods or describes previous works on the subject. For readers of the paper, the Reference section allows them to realize where the authors' hypotheses came from as well as other works in the field. This knowledge can be in the form of other journal articles, article abstracts, books, meeting results, or even websites, and APS has specific styles for each form of reference. This section of the Style Manual shows how to format the various types of references.