1. Grouplens: an open architecture for collaborative filtering of netnews;Resnick,1994
2. Empirical analysis of predictive algorithms for collaborative filtering;Breese,1998
3. Learning collaborative information filters;Billsus,1998
4. Item-based collaborative filtering recommendation algorithms;Sarwar,2001
5. Ego-centered networks and the ripple effect;Newman;Soc. Networks,2001