Bibliography
Black, Jeremy, and Anthony Green. Gods, Demons, and Symbols of Ancient Mesopotamia: An Illustrated Dictionary. Illustrations by Tessa Rickards. London, United Kingdom: The British Museum Press, 1992.
Cirlot Laporta, Juan Eduardo. A Dictionary of Symbols. Second Editions. Translated by Jack Sage. London, England: Routledge, 2001. [E-book edition by Taylor & Francis]
Mallory, James P., and Douglas Q. Adams. The Oxford Introduction to Proto-Indo-European and the Proto-Indo-European World. Oxford, United Kingdom: Oxford University Press, 2006.