"United States Census, 1920," database with images, FamilySearch (https://familysearch.org/ark:/61903/1:1:MH4M-3JH : accessed 20 May 2019), William T Cummings in household of William J Cummings, San Francisco Assembly District 30, San Francisco, California, United States; citing ED 224, sheet 2B, line 81, family 52, NARA microfilm publication T625 (Washington D.C.: National Archives and Records Administration, 1992), roll 139; FHL microfilm 1,820,139.
"United States Census, 1930," database with images, FamilySearch (https://familysearch.org/ark:/61903/1:1:XCN9-8G3 : accessed 20 May 2019), William Cummings in household of William J Cummings, San Francisco (Districts 251-409), San Francisco, California, United States; citing enumeration district (ED) ED 289, sheet 19A, line 33, family 367, NARA microfilm publication T626 (Washington D.C.: National Archives and Records Administration, 2002), roll 205; FHL microfilm 2,339,940.