Some book titles to get you started. This is not an exhaustive list!
Ethnicity challenged: the Upper Midwest Norwegian-American experience in World War I
Chrislock, Carl Henry, 1981.
The world at war
Brandes, Georg Morris Cohen, 1917.
Sweden, Norway, Denmark and Iceland in the world war
Heckscher, Eli F., et.al., 1930.
History of the world war: an authentic narrative of the world's greatest war
March, Francis Andrew; Beamish, Richard J; 1919.
Victory: Chisago County, Minnesota, in the World War.
Chisago County War History Committee, 1920.
Carry on Private Dahlgren: World War I runner, Company C, 349th Infantry, Minnesota: journals of Oscar R. Dahlgren, World War veteran during World War 1 combat.
Dahlgren, Oscar R.; Larson, Conrad., 2009.
War, peace, and the future: a consideration of nationalism and internationalism, and of the relation of women to war
Key, Ellen Karolina Sofia; Norberg, Hildegard, tr., 1916.
War letters home: letters of William (Bill) Edward Malmer, July 25-September 21, 1918
Malmer, William Edward; Malmer, Reynold W.; 2003.
All my born days: experiences of a naval intelligence officer in Europe
Gade, John A., 1942.
Hur kriget kom till Amerika
Committee on Public Information, 1917.
Minnesota in the war with Germany
Holbrook, Franklin F; Appel, Livia; 1928-1932.
St. Paul and Ramsey County in the war of 1917-1918
Holbrook, Franklin Fisk, 1929.
Finland, the buffer-state of Europe.
Hoving, Johannes Walter Wilhelm, 1915.