"Iowa, County Marriages, 1838-1934," index, FamilySearch (https://familysearch.org/pal:/MM9.1.1/XJXF-HD2 : accessed 16 Oct 2014), Richard J. Roorda and Agnes Hoekstra, 29 May 1912; citing Sheldon, O'Brien Co., Iowa, United States; FHL microfilm 1433427.