In history, science sources comprise texts, objects and facts which allow to derive knowledge of the past. Sources help to reconstruct circumstances on families and may serve as proof thereof. - The term literature was regularly used in science up to the 19th century. Currently, however, the term literature is used for published documents.
Reference books mostly contain lists in alphabetical order. They are available in printed as well as electronic mode and may be found in archives, libraries or in the internet.
Reference books are books usually of an alphabetically sorted list, books mostly in printed and in electronic form. They are available in archives, libraries or in the Internet.