"The Smallest Specimen Yet."
MLA
Hansen, Bert, 1944-. "The Smallest Specimen Yet.". Box 10, folder 12. 1890 February 19. https://collections.library.yale.edu/catalog/32331577.
APA, 6th edition
Hansen, Bert, 1944-. (["Box 10, folder 12"])(1890 February 19)["The Smallest Specimen Yet."]. https://collections.library.yale.edu/catalog/32331577.