Petsche, Johanna. “The Sacred Dance of the Enneagram: The History and Meanings Behind G. I. Gurdjieff’s Enneagram Movements”. Fieldwork in Religion 11, no. 1 (November 7, 2016): 53–75. Accessed December 7, 2021. https://journal.equinoxpub.com/FIR/article/view/13000.