"United States Census, 1900," database with images, FamilySearch (https://familysearch.org/ark:/61903/1:1:M3YP-GBB : accessed 6 September 2019), Mayer Monsky in household of Abram Monsky, Precinct 1 Omaha city Ward 2, Douglas, Nebraska, United States; citing enumeration district (ED) 10, sheet 1B, family 14, NARA microfilm publication T623 (Washington, D.C.: National Archives and Records Administration, 1972.); FHL microfilm 1,240,923.
"United States Census, 1940," database with images, FamilySearch (https://familysearch.org/ark:/61903/1:1:K99Z-322 : 27 July 2019), Mayer Monsky in household of Betsy Monsky, Ward 10, Omaha, Omaha City, Douglas, Nebraska, United States; citing enumeration district (ED) 94-153, sheet 7B, line 43, family 141, Sixteenth Census of the United States, 1940, NARA digital publication T627. Records of the Bureau of the Census, 1790 - 2007, RG 29. Washington, D.C.: National Archives and Records Administration, 2012, roll 2274.