"United States Census, 1920," index and images, FamilySearch (https://familysearch.org/pal:/MM9.1.1/MJSY-X72 : accessed 19 Oct 2013), Marie Slingerland in household of Hendry Greving, Chicago Ward 9, Cook (Chicago), Illinois, United States; citing sheet , family 151, NARA microfilm publication T625, FHL microfilm 1820311.