Authority control is a way of associating a unique identifier to articles on Wikipedia. This is useful to disambiguate different items with similar or identical headings, as well as establish a single standard title for an item that is commonly known by two or more titles. When used, authority control data links can be found near the bottom of Wikipedia pages, linking to bibliographical records on worldwide library catalogs. Authority control is often used on biographical articles because it is quite common for more than one person to share the same name. It is commonly used in other subject material, as well.