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Magaloni Kerpel, Diana. The Colors of the New World: Artists, Materials, and the Creation of the Florentine codex. Los Angeles, L.A.: Getty Research Institute, 2014.

Moctezuma, Eduardo Matos, and Felipe Solís. Aztecs. New-York: Harry N. Abrams, 2003. 

Pillsbury, Joanne. "Serpent Labret with Articulated Tongue." The Metropolitan Museum of Art. Accessed April 26, 2017.
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