WordPress categories may overlap, and here at the CPP website they often do. For example an article in a newsletter will appear under Newsletter, Articles, and Volume Number (V23), also in the year of publication under Archives. When viewing a post at this website, you will find categories for that post listed at the bottom of the entry. Clicking on a category name will return the archive for that category. And don’t forget to use the search function at the top right of the website to search for authors, etc.