"United States Census, 1920," index and images, FamilySearch (https://familysearch.org/pal:/MM9.1.1/MF9R-117 : accessed 26 Nov 2014), Elsie Heerdt in household of Nellie Jackman, Uxbridge, Worcester, Massachusetts, United States; citing sheet 28A, family 607, NARA microfilm publication T625, National Archives and Records Administration, Washington D.C.; FHL microfilm 1820748.