Generally there are different authority file headings and identifiers used by different libraries in different countries, possibly inviting confusion, but there are different approaches internationally to try to lessen the confusion. One international effort to prevent such confusion is the Virtual International Authority File which is a collaborative attempt to provide a single heading for a particular subject. It is a way to standardize information from different authority files around the world such as the Integrated Authority File (GND) maintained and used cooperatively by many libraries in German-speaking countries and the United States Library of Congress. The idea is to create a single worldwide virtual authority file. For example, the ID for Princess Diana in the GND is "118525123" (preferred name: "Diana <Wales, Prinzessin>") while the United States Library of Congress uses the term "Diana, Princess of Wales, 1961–1997"; other authority files have other choices. The Virtual International Authority File choice for all of these variations is "VIAF ID: 107032638" — that is, a common number representing all of these variations.