The credentials of the author of a book are frequently on the jacket, or at the beginning of a book. Web pages, like articles, may or may not present credentials. A common place to look for credentials on a Web pages 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 may affect the value of a recorded information source, and may help you verify the facts or conclusions presented.
Documentation is generally at the end of a book, article, or Web page.
Reviewed or edited articles tend to be more closely scrutinized for accuracy and value. Articles in professional or scholarly journals tend to have more reviewed and edited articles than popular magazines. Check the front of the periodical or book for information on the editing, review and selection process for that periodical. Web pages may have them at the beginning or end of a page, or on the home page of the site. The credentials of the author may give you clues to bias.