The credentials of the author of a book are frequently on the jacket, or at the beginning of a book. Web sites, like articles, may or may not present credentials. A common place for Web sites to list credentials is at the top or bottom of the page. You may have to go back to the home page of the site to see credentials. The amount and type of documentation used affects the value of your source and may help you verify the facts or conclusions presented.
Documentation generally consists of bibliography, footnotes, credits, sources, or quotations.
Documentation is usually at the end of a book, article, or Web page. Resources that include documentation are considered more reliable and scholarly. The credentials of the author may give you clues to bias. The purpose of the author in presenting ideas, opinions, or research may in part determine the usefulness of the source. On Web sites, there may be an about us, or about this site, or who we are page.