MLA

Hansen, Bert, 1944-. "Alonzo Garcelon Caesar I. The rule of Caesar is not success in this country; our 'Plain People' are not educated 'Up' to it'.". Box 4, folder 17. 1880 January 24. https://collections.library.yale.edu/catalog/32330086.

APA, 6th edition

Hansen, Bert, 1944-. (["Box 4, folder 17"])(1880 January 24)["Alonzo Garcelon Caesar I. The rule of Caesar is not success in this country; our 'Plain People' are not educated 'Up' to it'."]. https://collections.library.yale.edu/catalog/32330086.