How to Break Gifford's Cipher (extended abstract). - Thomas R. Cain; Alan T. Sherman (CCS, 1994)

Algebraic Software Testing in Vector Spaces of Functions. - Thomas R. Cain; E. K. Park (COMPSAC, 1996)

How to Break Gifford's Cipher. - Thomas R. Cain; Alan T. Sherman (Cryptologia, 1997)