羅傑的一張地圖：1869年時愛荷華州克雷頓郡古登堡的鳥瞰圖

出處: Ruger, A., panoramic map artist. "Bird's Eye View of Guttenberg, Clayton County, Iowa 1869." Merchants Lithographing Co. 1869. Panoramic Maps, 1847-1929, Library of Congress.