"United States Census, 1900," database with images, FamilySearch (https://familysearch.org/ark:/61903/1:1:MMR3-29F : accessed 16 September 2017), Martin Aberg in household of Ole L Aberg, Gray, Herrick & Norden Townships, Deuel, South Dakota, United States; citing enumeration district (ED) 133, sheet 12A, family 220, NARA microfilm publication T623 (Washington, D.C.: National Archives and Records Administration, 1972.); FHL microfilm 1,241,549.