1. Bobadilla, J., Ortega, F., Hernando, A., Gutierrez, A.: Recommender systems survey. Knowl. Based Syst. 46, 109–132 (2013)
2. Koren, Y., Sill, J.: Collaborative filtering on ordinal user feedback. In: International Joint Conference on Artificial Intelligence, pp. 3022–3026 (2013)
3. Zenebe, A., Norcio, A.F.: Representation, similarity measures and aggregation methods using fuzzy sets for content-based recommender systems. Fuzzy Sets Syst. 160(1), 76–94 (2009)
4. Boulkrinat, S., Hadjali, A., Aissani Mokhtari, A.: Handling preferences under uncertainty in recommender systems. In: IEEE International Conference on Fuzzy Systems, pp. 2262–2269 (2014)
5. Yu, K., Schwaighofer, A., Tresp, V., Xu, X., Kriegel, H.-P.: Probabilistic memory-based collaborative filtering. IEEE Trans. Knowl. Data Eng. 16(1), 56–69 (2004)