Cite

Letter to Miss Halsey

MLA

De Morgan, William, 1839-1917. Letter to Miss Halsey. Box 1, folder 4. 1891 Jun 14. https://collections.library.yale.edu/catalog/16445194.

APA, 6th edition

De Morgan, William, 1839-1917. (["Box 1, folder 4"])(1891 Jun 14)[Letter to Miss Halsey]. https://collections.library.yale.edu/catalog/16445194.