Preparation, characterization and photochromic behavior of phosphotungstic acid-ormosil nanocomposites - Ferreira Neto, Elias Paiva; Ullah, Sajjad; Carvalho, Flávio Luiz Silva de; Souza, Adriano Lopes de; Oliveira Junior, Marcos de; Schneider, José Fabian; Mascarenhas, Yvonne Primerano; Jorge Junior, Alberto Moreira; Rodrigues Filho, Ubirajara Pereira (Materials Chemistry and Physics, 2015)