"United States Census, 1920," index and images, FamilySearch (https://familysearch.org/pal:/MM9.1.1/MZQM-6XR : accessed 20 Apr 2014), Millard Devries in household of George Devries, Grand Rapids Ward 3, Kent, Michigan, United States; citing sheet 17B, family 409, NARA microfilm publication T625, FHL microfilm 1820779.
"United States Census, 1930," index and images, FamilySearch (https://familysearch.org/pal:/MM9.1.1/XQBK-8CJ : accessed 20 Apr 2014), Millard Devries in household of George Devries, Grand Rapids, Kent, Michigan, United States; citing enumeration district (ED) 0077, sheet 19B, family 295, NARA microfilm publication T626, roll 1003.