Hinrich Wulpern’s Certificate of United States of America Citizenship, 1889-03-09, Container: Trew Family - Box 2, Folder: 5 - Miscellaneous Wuelpern. Families, RG-FAMILIES. Hoyt Library Archives. https://archive.saginawlibrary.org/repositories/2/archival_objects/22655 Accessed December 15, 2025.