"This exhibition is the first retrospective fully dedicated to the drawings of Gustav Klimt (1862–1918)." View drawings made available by the Getty Museum.
Suggested terms to look for include - diary, diaries, letters, papers, documents, documentary or correspondence.
Combine these these terms with the event or person you are researching. (example: civil war diary)
Also search by subject for specific people and events, then scan the titles for those keywords or others such as memoirs, autobiography, report, or personal narratives.
