"United States Census, 1910," index and images, FamilySearch (https://familysearch.org/pal:/MM9.1.1/MG8Y-1KQ : accessed 01 Oct 2014), John Oppewal, Columbus, Warren, Pennsylvania, United States; citing enumeration district (ED) 152, sheet 5B, family 15, NARA microfilm publication T624, FHL microfilm 1375437.
"United States Census, 1920," index and images, FamilySearch (https://familysearch.org/pal:/MM9.1.1/M6BM-JJB : accessed 01 Oct 2014), John Oppewal, Columbus, Warren, Pennsylvania, United States; citing sheet 6A, family 128, NARA microfilm publication T625, FHL microfilm 1821657.