MLA

Wilder, Thornton, 1897-1975. Leigh, Vivien. Box 45, folder 1206-1207. 1944-60, n.d.. https://collections.library.yale.edu/catalog/17056652.

APA, 6th edition

Wilder, Thornton, 1897-1975. (["Box 45, folder 1206-1207"])(1944-60, n.d.)[Leigh, Vivien]. https://collections.library.yale.edu/catalog/17056652.