Gregorian-to-Aztec date conversion, with Aztec astrological notes.

A sixteenth-century account of the religion and history of the Colhua Mexica, or Aztecs.

A "technical manual" for the Aztec Calendar and Aztec's perception of God by Dr. Randall C. Jimenez and Richard Graeber.

Site breaks down all aspects of the Aztec calendric system