Canuto, S. D., F. M. Belém, J. M. Almeida, and M. A. Gonçalves. “A Comparative Study of Learning-to-Rank Techniques for Tag Recommendation”. Journal of Information and Data Management, vol. 4, no. 3, Sept. 2013, p. 453, doi:10.5753/jidm.2013.1509.