Sources are the sources used in the preparation of each article.
Source type: you can limit your search to books alone, or to other kinds of source.
Title: names of books and articles, or descriptions of manuscripts. Enter a word or an exact phrase.
Journal title: for newspapers and all periodicals.
Author surname and Initials: if you enter initials, leave spaces between them: H C G.
Year: the year of publication or, for manuscripts, creation. You can enter a single year, or use both Year fields to define a period.