"United States Census, 1850," index and images, FamilySearch (https://familysearch.org/pal:/MM9.1.1/MF8L-KD2 : accessed 15 January 2015), G J Mulder in household of W J Mulder, Holland, Ottawa, Michigan, United States; citing family 208, NARA microfilm publication M432 (Washington, D.C.: National Archives and Records Administration, n.d.).