George Bernard Shaw (2015). “George Bernard Shaw: Collected Articles, Lectures, Essays and Letters: Thoughts and Studies from the Renowned Dramaturge and Author of Mrs. Warren’s Profession, Pygmalion, Arms and The Man, Saint Joan, Caesar and Cleopatra, Androcles And The Lion”, p.294, e-artnow
Langston Hughes, Dolan Hubbard, Leslie Catherine Sanders (2001). “The Collected Works of Langston Hughes: Works for children and young adults: poetry, fiction, and other writing”, p.81, University of Missouri Press