The document discusses various types of biographical sources, including biographies, biographical dictionaries, and Who's Who publications. Biographies provide a full narrative account of a person's life written by another author. Biographical dictionaries contain alphabetical listings of people with key dates and events. Who's Who publications contain concise biographical profiles of notable individuals from various fields. The document provides examples of prominent biographical references, such as the American National Biography, UK Who's Who, and publications from Marquis Who's Who.