"United States Census, 1880," index and images, FamilySearch (https://familysearch.org/pal:/MM9.1.1/MN4N-3K7 : accessed 5 February 2015), Jacob P Bakker, Alto, Fond du Lac, Wisconsin, United States; citing enumeration district 30, sheet 17D, NARA microfilm publication T9 (Washington D.C.: National Archives and Records Administration, n.d.), roll 1425; FHL microfilm 1,255,425.