@InProceedings {ddps-spds2004,
    author = {E. Damiani and S. {De Capitani di Vimercati} and S. Paraboschi and P. Samarati},
    booktitle = {Proc. of the 2004 International Workshop on Security in Parallel and Distributed Systems},
    title = {An Open Digest-based Technique for Spam Detection},
    address = {San Francisco, CA, USA},
    month = {September},
    day = {15-17},
    year = {2004}
}