"United States Census, 1850," index and images, FamilySearch (https://familysearch.org/pal:/MM9.1.1/MF82-BSB : accessed 2 February 2015), Hendrik Wierema, Spring Lake, Ottawa, Michigan, United States; citing family 587, NARA microfilm publication M432 (Washington, D.C.: National Archives and Records Administration, n.d.).