MLA

Doyle, Arthur Conan, 1859-1930. Letter : Crowborough, Sussex, to George Meredith. Box 50, folder GROUP 1703, F-2. 1909 Jan 19. https://collections.library.yale.edu/catalog/33426980.

APA, 6th edition

Doyle, Arthur Conan, 1859-1930. (["Box 50, folder GROUP 1703, F-2"])(1909 Jan 19)[Letter : Crowborough, Sussex, to George Meredith]. https://collections.library.yale.edu/catalog/33426980.