In some instances, published materials can also be viewed as primary materials for the period in which they were written."
Historians use primary sources as evidence. Additional examples of primary sources are diaries, personal journals, government records, court records, property records, military reports, and military rosters.
Listed below are some relevant databases for locating journal articles & other resources:
Full-text access to journals across the disciplines
The ASU Libraries have several E-Book collections. Each can be searched distinctly the same as a database BUT you will see only those titles published as part of that collection. E-books are also included in the Libraries Catalog the same as traditional print/paper books which means you can search all e-book collections plus print books at once by searching the Catalog. To limit your search results to online books use the "Advanced Search" mode and in LOCATION, limit results to 'Online Access'. Many e-book vendors allow you to set up a free account to personalize settings for viewing & using. They also generally limit the number of pages that can be printed or downloaded in compliance with copyright laws.