1. R.M. Needham and A.D. Birrell 'The CAP Filing System' SOSP6 1977 10.1145/800214.806542 R.M. Needham and A.D. Birrell 'The CAP Filing System' SOSP6 1977 10.1145/800214.806542
2. R.M. Needham and R.D.H. Walker 'The Cambridge CAP Computer and its Protection System' SOSP6 1977. 10.1145/800214.806541 R.M. Needham and R.D.H. Walker 'The Cambridge CAP Computer and its Protection System' SOSP6 1977. 10.1145/800214.806541