@article{amati02randomness,
 author = {Amati, G. and Van Rijsbergen, C. J.},
 title = {Probabilistic models of Information Retrieval based on measuring divergence from randomness},
 year = {2002},
 journal = {ACM Transactions on Information Systems},
 volume = {20},
 number = {4},
 pages = {357--389},
}