George Santayana, Marianne S. Wokeck, Martin A. Coleman, James Gouinlock (2015). “The Life of Reason Or The Phases of Human Progress: Reason in Art, Volume VII, Book Four”, p.118, MIT Press
Jalāl al-Dīn Rūmī (Maulana), Jelaluddin Rumi, Kabir Helminski, Andrew Harvey (2005). “The Rumi Collection: An Anthology of Translations of Mevlâna Jalâluddin Rumi”, p.73, Shambhala Publications