Paper on early maize in Peru

Today I read this paper.

• Grobman, A., D. Bonavia, T.D. Dillehay, D.R. Piperno, J. Iriarte, I. Holst. 2012. Preceramic Maize from Paredones and Huaca Prieta, Peru. Proceedings of the National Academy of Science (PNAS) Early Edition: 1-5.