MLA

Gissing, George, 1857-1903. "Answer to Goldsmith's Criticism on Hamlet's Soliloquy". Box 6, folder 100. 1872 Jul 22. https://collections.library.yale.edu/catalog/16495588.

APA, 6th edition

Gissing, George, 1857-1903. (["Box 6, folder 100"])(1872 Jul 22)["Answer to Goldsmith's Criticism on Hamlet's Soliloquy"]. https://collections.library.yale.edu/catalog/16495588.