Tolong jelaskan mengenai Sumber primer dari Orang Jerman Amerika

Kamphoefner, Walter D., and Wolfgang Helbich (Eds.). Germans in the Civil War; The Letters They Wrote Home. Chapel Hill: University of North Carolina Press, 2006.

Kamphoefner, Walter D., Wolfgang Johannes Helbich and Ulrike Sommer (Eds.). News from the Land of Freedom: German Immigrants Write Home. Ithaca: Cornell University Press, 1991.

(English translations of selected German-language newspaper articles, 1855-1938).