@Article {dfpps-tcc2018,
    author = {S. {De Capitani di Vimercati} and S. Foresti and S.
Paraboschi and G. Pelosi and P. Samarati},
    title = {Three-Server Swapping for Access Confidentiality},
    journal = {IEEE Transactions on Cloud Computing (TCC)},
    volume = {6},
    number = {2},
    pages = {492-505},
    month = {April-June},
    year = {2018}
}