Defects excitation and photoconductivity dependence of Sn´O IND.2´sol-gel films with several ligh sources - Messias, Fábio Rogério; Scalvi, L. V. A.; Siu Li, Máximo; Vega, Bárbara A. V.; Santilli, C. V.; Pulcinelli, S. H. (Europhysical Conference on Defects in Insulating Materials, 1998)