Several papers of interest here:

The Netflix Prize
James Bennett and Stan Lanning

Improved Neighborhood-based Collaborative Filtering
Robert M. Bell and Yehuda Koren

Variational Bayesian Approach to Movie Rating Prediction
Yew Jin Lim and Yee Whye Teh

On the Gravity Recommendation System
Gabor Takacs, Istvan Pilaszy, Bottyan Nemeth, and Domonkos Tikk

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