↑ Find a Grave, database and images (https://www.findagrave.com : accessed 01 March 2021), memorial page for Ida Helen McKinley Cooper (13 Oct 1870–30 Mar 1911), Find A Grave: Memorial #5950174, citing Greenlawn Memorial Park, Colma, San Mateo County, California, USA ; Maintained by Janet LaMotte, MHR (contributor 46988542) .'
↑ "New York, New York City Marriage Records, 1829-1940," database, FamilySearch (https://familysearch.org/ark:/61903/1:1:24CM-PLG : 10 February 2018), Harry Cooper and Ida Morse, 14 Jan 1905; citing Marriage, Manhattan, New York, New York, United States, New York City Municipal Archives, New York; FHL microfilm 1,556,970.
↑ "United States Census, 1880," database with images, FamilySearch (https://familysearch.org/ark:/61903/1:1:M6G2-YC9 : 19 February 2021), Ida Hellen Mckinley in household of David A Mckinley, Oakland, Alameda, California, United States; citing enumeration district ED 9, sheet 170C, NARA microfilm publication T9 (Washington, D.C.: National Archives and Records Administration, n.d.), FHL microfilm 1,254,061.