Mining unstructured content for recommender systems: an ensemble approach - Manzato, Marcelo Garcia; Domingues, Marcos A; Fortes, Arthur C; Sundermann, Camila V; D'Addio, Rafael M; Conrado, Merley S; Rezende, Solange Oliveira; Pimentel, Maria da Graça Campos (Information Retrieval Journal, 2016)