Leslie S. Offutt, "Levels of Acculturation in Northeastern New Spain; San Esteban Testaments of the Seventeenth and Eighteenth Centuries," Estudios de cultura náhuatl 22 (1992), 409–443, see page 438–439.
James Lockhart, Nahuatl as Written: Lessons in Older Written Nahuatl, with Copious Examples and Texts (Stanford: Stanford University Press and UCLA Latin American Studies, 2001), 223.