Popp & Wolf, 1888-03-24, 1889-08-07, 1892-02-20, 1905-02-24, 1890-03-19, 1892-07-27, 1908-07-03, Container: Letterheads of Saginaw Businesses - Box 1, Folder: Three. Business and Industry, COL-BUSINESS. Hoyt Library Archives. https://archive.saginawlibrary.org/repositories/2/archival_objects/11979 Accessed December 15, 2025.