@Article {jsss.tods01,
    author = {S. Jajodia and P. Samarati and {M.L.} Sapino and {V.S.} Subrahmanian},
    title = {Flexible Support for Multiple Access Control Policies},
    journal = {ACM Transactions on Database Systems (TODS)},
    volume = {26},
    number = {2},
    pages = {214-260},
    month = {June},
    year = {2001}
}