1. Armah, P.W., 2001. The Determinants of Eco-label Usage in The Organic Produce Market of Northeast Arkansas. Selected Paper. American Agricultural Economics Association Annual Meeting. Aug. 5-8. Chicago, IL.
2. Cobo, F.B., y González, L., 2001. La agricultura ecológica ante la gran distribución. Revista Distribución y Consumo. Año 11. Núm. 60. Nov-Dic.
3. Gómez Cruz, M.A., Gómez Tovar, L., Schwentesius, R., 2006. Global Organic Production. Vinculando.org. Jul 23. Mazatlán 73-1, Col. Condesa; C.P. 06140; Ciudad de México, México. Available from: .
4. Free competition and the optimal amount of fraud;Darby;J. Law Eco.,1973
5. Food Marketing Institute and Prevention Magazine, 1997. Shopping for Health 1997: Balancing Convenience, Nutrition and Taste. Princeton, HF, Washington, DC and Emmaus, PA.