I. Introduction
Over the last years, the increasingly easy access to online services for listening to music, made it possible for users to have access to millions of songs on the Internet. However, when dealing with this overwhelming number of songs to choose from, they often become paralyzed and doubtful (The Paradox of Choice [1]). To reduce the burden of choosing among too many items, researchers have focused on creating recommender systems that can automatically generate recommendations that fit users' preferences.