"A City Ambulance."
MLA
Hansen, Bert, 1944-. "A City Ambulance.". Box 4, folder 15. 1879 May 31. https://collections.library.yale.edu/catalog/32332545.
APA, 6th edition
Hansen, Bert, 1944-. (["Box 4, folder 15"])(1879 May 31)["A City Ambulance."]. https://collections.library.yale.edu/catalog/32332545.