"Illinois, Cook County, Birth Certificates, 1871-1940," database, FamilySearch (https://familysearch.org/ark:/61903/1:1:Q23S-S3VC : 18 May 2016), Otis Bryant Thayer in entry for Florence Marguerite Thayer, 29 Nov 1890; Oak Park, Cook, Illinois, United States, reference/certificate 31823, Cook County Clerk, Cook County Courthouse, Chicago; FHL microfilm .
