MLA

Grinnell, Julius S. (Julius Sprague), 1842-1898. "To the Workmen. / An die Arbeiter Chicago's!", broadside published by Central Labor Union of Chicago. Box 5, folder 94. [ca. 1886]. https://collections.library.yale.edu/catalog/2007530.

APA, 6th edition

Grinnell, Julius S. (Julius Sprague), 1842-1898. (["Box 5, folder 94"])([ca. 1886])["To the Workmen. / An die Arbeiter Chicago's!", broadside published by Central Labor Union of Chicago]. https://collections.library.yale.edu/catalog/2007530.