"United States Census, 1860," index, FamilySearch (https://familysearch.org/pal:/MM9.1.1/M8L7-7XY : accessed 16 February 2015), Feike Heemstra in household of Franciscus Mak, Summit Township, Marion, Iowa, United States; from "1860 U.S. Federal Census - Population," Fold3.com; citing p. 179, household ID 1209, NARA microfilm publication M653, National Archives and Records Administration, Washington, D.C.; FHL microfilm 803,335.