"United States Census, 1940," database with images, FamilySearch (https://familysearch.org/ark:/61903/1:1:K7FC-3RR : 6 February 2020), Shirley Ann Barnes in household of John M Barnes, Walkersville, Election District 26, Frederick, Maryland, United States; citing enumeration district (ED) 11-61, sheet 3B, line 57, family 63, 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 1549.