The published pages, books, encyclopedias, biographies and archives every fact and citation in the Mathematics Atlas is checked against, one source entity per distinct published page or work regardless of how many facts it supports. Belongs here: encyclopedia articles, biography pages, primary texts, faculty pages and the other reference material cited on entity pages. Does not belong here: the mathematicians, theorems and other subjects a source supports, filed under their own type and reached from the source through the citation naming it.