When you are working with citations or references, it is helpful to understand the parts and pieces. Below are two examples of citations, one from an article database and the second from a bibliography. Note that they are laid out differently and although the elements may look different they contain the same information. Each has a source - where the information is from. It could be a book, or a conference proceeding or a journal article or many other types of materials. In the case of these, there will also be the article title or for a book perhaps a chapter title. For journal articles there will be a volume number and an issue number. Sometimes the issue in the form of a date, but for books the publication date will always be listed along with an edition. Both will include a page range unless the entire book is cited and then it will list the total number of pages. The ISSN is the unique number assigned to every journal just as the ISBN is unique to each book. Databases also provide a wide array of other information such as author affiliations, an abstract, key concepts or index terms which are generally labeled as they are below.