"United States Census, 1940," index and images, FamilySearch (https://familysearch.org/pal:/MM9.1.1/K4NL-BG7 : accessed 22 Sep 2014), Sidney Jorritsma in household of Agnes Hornstra, Hingham Town, Plymouth, Massachusetts, United States; citing enumeration district (ED) 12-100, sheet 9A, family 184, NARA digital publication of T627, roll 1638.