MLA

Cassirer, Ernst, 1874-1945. "Hermann Cohens Philosophie in ihrem Verhältnis zum Judentum": outline and research notes to lecture (Envelope #207). Box 38, folder 731. 1931 Apr 12. https://collections.library.yale.edu/catalog/17274627.

APA, 6th edition

Cassirer, Ernst, 1874-1945. (["Box 38, folder 731"])(1931 Apr 12)["Hermann Cohens Philosophie in ihrem Verhältnis zum Judentum": outline and research notes to lecture (Envelope #207)]. https://collections.library.yale.edu/catalog/17274627.