Optical and physical properties of aerosols in the boundary layer and free troposphere over the Amazon Basin during the biomass burning season - Chand, D.; Guyon, P.; Artaxo, P.; Schmid, O.; Frank, G. P.; Rizzo, L. V.; Mayol-Bracero, O. L.; Gatti, L. V.; Andreae, M. O. (Atmos. Chem. Phys., 2006)