To find these primary sources use the Advance search option on UW Libraries Search
By AUTHOR-- search for books written by key participants and organizations.
By SPECIAL SUBJECT HEADINGS -- do a keywords search for your topic/event and in the second box change the label from "Title" to "Identifier, Subject" and use one of these special subject headings that designate primary sources: personal narratives, correspondence, diaries, interviews, sources. Some terms may work better than others depending on your topic.
By DATE -- narrow your search by year of publication
The UW Libraries has a strong collection of published primary sources dealing with history. These include:
Books written during the period for your topic (e.g., during the 1850s)
Books written by participants
Published collections of correspondence and diaries
Memoirs & autobiographies
Reprinted of collections of primary source material