MLA

Grinnell, Julius S. (Julius Sprague), 1842-1898. Maul, J., photographs of Engel, Fielden, Lingg, Neebe, Parsons, and Schwab, cabinet cards. Box 6, folder 104. n.d.. https://collections.library.yale.edu/catalog/2012889.

APA, 6th edition

Grinnell, Julius S. (Julius Sprague), 1842-1898. (["Box 6, folder 104"])(n.d.)[Maul, J., photographs of Engel, Fielden, Lingg, Neebe, Parsons, and Schwab, cabinet cards]. https://collections.library.yale.edu/catalog/2012889.