Here are some book titles to get you started. This is not an exhaustive list!
The Civil war in song and story, 1860-1865
Moore, Frank, 1882.
The Story of a private in the Civil War: the experiences of Gus Alstrand of Fort Dodge, in battle and as a prisoner in the Andersonville stockade.
Alstrand, Gustaf, 1970.
Colonel Heg and his boys: a Norwegian regiment in the American Civil War
Ager, Waldemar, 2000.
The civil war letters of Colonel Hans Christian Heg
Heg, Hans Christian; Blegen, Theodore Christian (ed); 1936.
Minnesota in the Civil and Indian wars, 1861-1865
Minnesota Historical Society, 2005.
Swedish immigrants in Lincoln's time
Hokanson, Nels Magnus, 1942.
The diary of James T. Ayers, Civil War recruiter
Ayers, James T.; Franklin, John Hope, (ed); 1947.
Two wars on the frontier: diaries of A. J. Carlson
Carlson, A. J. (Andrew John); Biorn, Wendy Peterson (ed); 2014.
Skizzer från nord-amerikanska kriget, 1861-1865. Bref och anteckningar under en fyraårig vistelse i Förenta Staterna
Warberg, Adolf Carlsson, 1867.
För adoptivlandets och mänsklighetens sak: svenskarna i Illinois och det amerikanska inbördeskriget
Kvist, Roger, 2003.