"United States Census, 1860," index, FamilySearch (https://familysearch.org/pal:/MM9.1.1/MWDZ-LJ1 : accessed 24 December 2014), John De Groot, The Town Of Zeeland, Ottawa, Michigan, United States; from "1860 U.S. Federal Census - Population," Fold3.com; citing p. 66, household ID 510, NARA microfilm publication M653, National Archives and Records Administration, Washington, D.C.; FHL microfilm 803,557.