Question: 1. Martin Gardner. "A New Kind of Cipher That Would Take Millions of Years to Break." Scientific American 237, No. 2 (August 1977).
2. Patricia P. Griffiths and Bradford W. Wade. "An Authorization Mechanism for a Rela-tional Data Base System." ACM PODS I, No. 3 (September 1976). Describes the GRANT and REVOKE mechanism originally proposed for System R. The scheme now included in the SQL standard is based on that mechanism, though significantly different in detail.