"United States Census, 1880," database with images, FamilySearch (https://familysearch.org/ark:/61903/1:1:M8YZ-124 : 16 August 2017), William Wilks in household of Fred Procknow, Saratoga, Douglas, Nebraska, United States; citing enumeration district ED 27, sheet 372C, NARA microfilm publication T9 (Washington, D.C.: National Archives and Records Administration, n.d.), FHL microfilm 1,254,748.