"United States Census, 1900," index and images, FamilySearch (https://familysearch.org/pal:/MM9.1.1/M3BD-6JP : accessed 24 February 2015), Yella De Vries, South Pass Precinct Firth village, Lancaster, Nebraska, United States; citing sheet 1A, family 9, NARA microfilm publication T623 (Washington, D.C.: National Archives and Records Administration, n.d.); FHL microfilm 1,240,934.