Steve J. Chapin Chenxi Wang William A. Wulf Frederick Knabe Andrew S. Grimshaw A new model of security for metasystems. 713-722 1999 15 Future Generation Comp. Syst. 5-6 http://dx.doi.org/10.1016/S0167-739X(99)00021-7 db/journals/fgcs/fgcs15.html#ChapinWWKG99