Plotinus and the Presocratics: A Philosophical Study of Presocratic Influences in Plotinus' Enneads S U N Y Series in Ancient Greek Philosophy By Giannis Stamatellos SUNY Press, 2007 ISBN 0791470628, 9780791470626 [1]
pg 52 The Mystery religions: A Study in the Religious Background of Early Christianity By Samuel Angus 1920 republished by Courier Dover Publications, 1975
ISBN 0-486-23124-0, ISBN 978-0-486-23124-2[2][3]
Neoplatonism and Indian Philosophy By Paulos Gregorios, International Society for Neoplatonic Studies [4]
Reiner Schürmann (29 de outubro de 2003). Broken Hegemonies. [S.l.]: Indiana University Press. pp. 109–. ISBN978-0-253-11053-4. Consultado em 22 de abril de 2013