Wilhelmine was born in 1841. She passed away in 1921.
1) "United States Census, 1910," database with images, FamilySearch (https://familysearch.org/ark:/61903/1:1:MLTD-D9P : accessed 19 June 2019), Minnie Bortz in household of Charlie Bortz, Sumpter, Wayne, Michigan, United States; citing enumeration district (ED) ED 306, sheet 1A, family 2, NARA microfilm publication T624 (Washington D.C.: National Archives and Records Administration, 1982), roll 679; FHL microfilm 1,374,692.
2) Michigan Death Certificates, 1921-1952," database, FamilySearch (https://familysearch.org/ark:/61903/1:1:KF7G-9VP : 13 March 2018), Minnie Reamer in entry for Charles Fredrick Bortz, 24 Jul 1923; citing Ypsilanti, Washtenaw, Michigan, United States, Division for Vital Records and Health Statistics, Lansing; FHL microfilm 1,973,129.
3) "Michigan Marriages, 1868-1925", database with images, FamilySearch (https://familysearch.org/ark:/61903/1:1:N3XV-5FZ : 15 January 2019), Riemer in entry for Chas F Bortz and Mary Macks, 1897.