«'Oldest' New World writing found». BBC. 14 de septiembre de 2006. Consultado el 30 de marzo de 2008. «Ancient civilisations in Mexico developed a writing system as early as 900 BC, new evidence suggests.»
«Oldest Writing in the New World». Science. Consultado el 30 de marzo de 2008. «A block with a hitherto unknown system of writing has been found in the Olmec heartland of Veracruz, Mexico. Stylistic and other dating of the block places it in the early first millennium before the common era, the oldest writing in the New World, with features that firmly assign this pivotal development to the Olmec civilization of Mesoamerica.»
