Azambuja Silveira, R., R. Lunardi Comarella, R. Lima Rocha Campos, J. Vian, and F. De La Prieta. “Learning Objects Recommendation System: Issues and Approaches for Retrieving, Indexing and Recomend Learning Objects”. ADCAIJ: Advances in Distributed Computing and Artificial Intelligence Journal, vol. 4, no. 4, Dec. 2015, pp. 69-82, doi:10.14201/ADCAIJ2015446982.