Ralph Waldo Emerson, Robert Ernest Spiller, Alfred Riggs Ferguson, Joseph Slater, Jean Ferguson Carr (1971). “The Collected Works of Ralph Waldo Emerson”, p.215, Harvard University Press
Nathaniel Hawthorne, Herman Melville, Julian Hawthorne (2015). “Life and Genius of Nathaniel Hawthorne: Letters, Diaries, Reminiscences and Extensive Biographies: Autobiographical Writings of the Renowned American Novelist, Author of “The Scarlet Letter”, “The House of Seven Gables” and “Twice-Told Tales””, p.817, e-artnow
Ralph Waldo Emerson, Robert Ernest Spiller, Alfred Riggs Ferguson, Joseph Slater, Jean Ferguson Carr (1971). “The Collected Works of Ralph Waldo Emerson”, p.215, Harvard University Press