:That's because there are many different authority control standards, not only does VIAF offer this service, but so does the US Library of Congress (LCCN) and German National Library (PND) etc. However VIAF is a "bridge identifier" which means that ideally if you had the VIAF ID of person you could find their LCCN and PND, by searching at viaf.org . The matching is still not 100% complete or accurate, but that's the theory. Given that theory I am attempting only to place the VIAF numbers, and on commons people have different opinions.