MLA

Pryce-Jones, Alan, 1908-2000. Spark, Muriel. Box 23, folder 1134. 1963-64, n.d.. https://collections.library.yale.edu/catalog/17476536.

APA, 6th edition

Pryce-Jones, Alan, 1908-2000. (["Box 23, folder 1134"])(1963-64, n.d.)[Spark, Muriel]. https://collections.library.yale.edu/catalog/17476536.