Cite

Little blue book [subscription card for] Life and Letters

MLA

Haldeman-Julius, E. (Emanuel), 1888-1951. Little blue book [subscription card for] Life and Letters. Undated. https://collections.library.yale.edu/catalog/10779509.

APA, 6th edition

Haldeman-Julius, E. (Emanuel), 1888-1951. (Undated)[Little blue book [subscription card for] Life and Letters]. https://collections.library.yale.edu/catalog/10779509.