"Illinois, Cook County, Birth Certificates, 1871-1949," database, FamilySearch (https://familysearch.org/ark:/61903/1:1:NQY6-HRM : 18 May 2016), Horace William Mckay in entry for Russel Mckay, 14 Nov 1902; Chicago, Cook, Illinois, United States, reference/certificate 11551, Cook County Clerk, Cook County Courthouse, Chicago; FHL microfilm 1,288,045.
"Illinois, Cook County Deaths, 1871-1998," database, FamilySearch (https://familysearch.org/ark:/61903/1:1:Q2MF-SJ5W : 18 March 2018), Horace Mckay in entry for Russell J McKay, 18 Dec 1968; citing Chicago, Cook, Illinois, United States, source reference , record number , Cook County Courthouse, Chicago; FHL microfilm .