Sometimes within a catalog there are diverse names or spellings for only one person or subject. This variation may cause researchers to overlook relevant information. Authority control is used by catalogers to collocate materials that logically belong together but that present themselves differently. Records are used to establish uniform titles that collocate all versions of a given work under one unique heading even when such versions are issued under different titles. With authority control, one unique preferred name represents all variations and will include different variations, spellings and misspellings, uppercase versus lowercase variants, differing dates, and so forth. For example, in Wikipedia, the first wife of Charles, Prince of Wales is described by an article Diana, Princess of Wales as well as numerous other descriptors, e.g. Princess Diana, but both "Princess Diana" and "Diana, Princess of Wales" describe the same person; an authority record would choose one title as the preferred one for consistency. In an online library catalog, various entries might look like the following: