@InProceedings {bbs.ccs94,
    author = {E. Bertino and C. Bettini and P. Samarati},
    booktitle = {Proc. of the 2nd ACM Conference on Computer and Communications Security},
    title = {A Temporal Authorization Model},
    address = {Fairfax, VA},
    pages = {126-135},
    month = {Novemver},
    year = {1994}
}