William Butler Yeats, Richard J. Finneran, George Bornstein (2007). “The Collected Works of W.B. Yeats Volume IV: Early Essays”, p.185, Simon and Schuster
William Butler Yeats, Richard J. Finneran, George Bornstein (2007). “The Collected Works of W.B. Yeats Volume IV: Early Essays”, p.8, Simon and Schuster