File Security in Wordperfect 5.0. - Helen A. Bergen; William J. Caelli (Cryptologia, 1991)

Data security in a fixed-model arithmetic coding compression algorithm. - Helen A. Bergen; James M. Hogan (Comput. Secur., 1992)

A chosen plaintext attack on an adaptive arithmetic coding compression algorithm. - Helen A. Bergen; James M. Hogan (Comput. Secur., 1993)