Proof of Labor Files; 1880s (Loose Files)
Proof of Labor Files; 1890s (Loose Files)
Proof of Labor Files; 1900s (Loose Files)
Proof of Labor Files; 1910s (Loose Files)
Proof of Labor Files; 1920s (Loose Files)
Proof of Labor Files; 1930s (Loose Files)
Proof of Labor Files; 1940s (Loose Files)