MLA

Henri, Robert, 1865-1929. Correspondence. Box 12, folder 314. 1890 Jul. https://collections.library.yale.edu/catalog/17029581.

APA, 6th edition

Henri, Robert, 1865-1929. (["Box 12, folder 314"])(1890 Jul)[Correspondence]. https://collections.library.yale.edu/catalog/17029581.