@inproceedings{1042983,
    title = "Usage-based charging for internet usage: a case study",
    author = "Αποστολόπουλος, Θεόδωρος and Cohen, Sandra and Courcoubetis, Costas and Psiakki, Xanthi",
    year = "2000",
    pages = "52-72",
    publisher = "World Scientific",
    booktitle = "Advances in informatics. 7th Hellenic Conference on Informatics (HCI '99)"
}