Essential Library of World War I: World War I Causes
Military Technology: Top Secret Clearance: Warplanes of World War II Up Close
Frontline Families: World War I: Frontline Soldiers and Their Families
Tech in the Trenches: Strategic Inventions of World War I
Essential Library of World War I: Women in World War I
Critical Insights: Holocaust Literature
Essential Library of World War I: World War I Weapons
Defining Documents in American History: The 1900s (1900-1909)
Essential Library of World War I: World War I Battles
Primary Sources in U.S. History: World War II
Tech in the Trenches: Strategic Inventions of World War II