Gemmell, J., Ramezani, M., Schimoler, T., Christiansen, L. & Mobasher, B. (2009). The impact of ambiguity and redundancy on tag recommendation in folksonomies. RecSys '09: Proceedings of the third ACM conference on Recommender systems (p./pp. 45--52), New York, NY, USA: ACM. ISBN: 978-1-60558-435-5