MLA

Rudge, Olga, 1895-1996. Yeats-Pound memorial. Box 13, folder 523. n.d.. https://collections.library.yale.edu/catalog/17082117.

APA, 6th edition

Rudge, Olga, 1895-1996. (["Box 13, folder 523"])(n.d.)[Yeats-Pound memorial]. https://collections.library.yale.edu/catalog/17082117.