1. Instituto Nacional de Pediatría, Mexico City, Mexico
2. The Center for Structural and Functional Neurosciences, University of Montana, Missoula, Montanta, USA
3. Inhalation Toxicology and Aerobiology Section, Safe Environments Programme, Health Canada, Ottawa, Ontario, Canada
4. Escuela Médico Militar, Universidad del Ejército y Fuerza Aérea, México
5. Departamento de Estadística, Universidad de Valparaíso, Valparaíso, Chile
6. Centro de Ciencias de la Atmósfera, Universidad Nacional Autónoma de México, Mexico City, Mexico
7. Department of Medicine
8. Center for Environmental Medicine, Asthma and Lung Biology and
9. Department of Pediatrics, University of North Carolina, Chapel Hill, North Carolina, USA