MLA

Wolff, Kurt, 1887-1963. Starke, Ottomar. Box 7, folder 285-86. 1915-20, n.d.. https://collections.library.yale.edu/catalog/2021364.

APA, 6th edition

Wolff, Kurt, 1887-1963. (["Box 7, folder 285-86"])(1915-20, n.d.)[Starke, Ottomar]. https://collections.library.yale.edu/catalog/2021364.