Martha Patricia Sierra-Vargas* , Alberto Martin Guzman-Grenfell* , Salvador Blanco-Jimenez* , Jose David Sepulveda-Sanchez* , Rosa Maria Bernabe-Cabanillas* , Beatriz Cardenas-Gonzalez* , Guillermo Ceballos* and Juan Jose Hicks
Journal of Occupational Medicine and Toxicology 2009, 4:17doi:10.1186/1745-6673-4-17