MLA

Stevenson, Robert Louis, 1850-1894. Material removed from Graham Balfour's The Life of Robert Louis Stevenson. Box 13, folder 250-252. 1868-1922, undated. https://collections.library.yale.edu/catalog/10257652.

APA, 6th edition

Stevenson, Robert Louis, 1850-1894. (["Box 13, folder 250-252"])(1868-1922, undated)[Material removed from Graham Balfour's The Life of Robert Louis Stevenson]. https://collections.library.yale.edu/catalog/10257652.