Cite

"Dr. Koch at Work in His Laboratory."

MLA

Hansen, Bert, 1944-. "Dr. Koch at Work in His Laboratory.". Box 12, folder 19. 1890 December 6. https://collections.library.yale.edu/catalog/32333700.

APA, 6th edition

Hansen, Bert, 1944-. (["Box 12, folder 19"])(1890 December 6)["Dr. Koch at Work in His Laboratory."]. https://collections.library.yale.edu/catalog/32333700.