MLA

Smith, Albert A. The Reason. National Association for the Advancement of Colored People, 1920. https://collections.library.yale.edu/catalog/2002530.

APA, 6th edition

Smith, A. A. (1920). The Reason [Magazines (periodicals)]. National Association for the Advancement of Colored People. https://collections.library.yale.edu/catalog/2002530.