MLA

Hansen, Bert, 1944-. "A Warning Light. Will it be necessary to erect an admonition of pestilence and death in our harbor? A question which our citizens must decide.". Box 4, folder 26. 1881 April 2. https://collections.library.yale.edu/catalog/32330134.

APA, 6th edition

Hansen, Bert, 1944-. (["Box 4, folder 26"])(1881 April 2)["A Warning Light. Will it be necessary to erect an admonition of pestilence and death in our harbor? A question which our citizens must decide."]. https://collections.library.yale.edu/catalog/32330134.