MLA

Hansen, Bert, 1944-. "Getting Troublesome Again. Uncle Sam 'I guess he won't stop howling till I give him enough Protection Soothing Syrup to burst him'!". Box 10, folder 26. 1896 December 30. https://collections.library.yale.edu/catalog/32331619.

APA, 6th edition

Hansen, Bert, 1944-. (["Box 10, folder 26"])(1896 December 30)["Getting Troublesome Again. Uncle Sam 'I guess he won't stop howling till I give him enough Protection Soothing Syrup to burst him'!"]. https://collections.library.yale.edu/catalog/32331619.