So far I had found none.
An interesting read [Google Docs Viewer Link] (https://docs.google.com/viewer?a=v&q=cache:NLMEk1CsCYkJ:www.cs.umd.edu/projects/MusicDigger/MusicDigger_Final_Report.pdf+&hl=es&gl=cl&pid=bl&srcid=ADGEESiauNo4Q1kC2ccozGyLmAehOPqP4vHP4r6UA5eqV3H8ljdmL1JpRWy5ZQ5bkpZfX4TGa8mrXLcrN_d2MH0aoR1nrUNRN6UmVoBC4995bH1pYBunZuvCO9iHDp9S7srR9OhI3hRB&sig=AHIEtbSiz3VohgU4iVbefcp6PdWa57dm5Q) that describes how music recommendation engines such as Pandora and Last.fm work.