"United States Census, 1940," database with images, FamilySearch (https://www.familysearch.org/ark:/61903/1:1:KQR9-5BN : 7 January 2021), Margaret Gillen in household of Michael Gillen, Brooklyn, New York City, New York, United States; citing enumeration district (ED) 24-491, sheet 7A, line 8, family 128, 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 2559.