"United States Census, 1940," index and images, FamilySearch (https://familysearch.org/pal:/MM9.1.1/KQFW-FWY : accessed 03 Oct 2014), Henry Wykstra, Ward 1, Titusville, Titusville City, Crawford, Pennsylvania, United States; citing enumeration district (ED) 20-53A, sheet 2B, family 55, NARA digital publication of T627, roll 3477.