Cycle structure of the DES with weak and semi-weak keys

Moore, J. H., & Simmons, G. J. (1987). Cycle structure of the DES with weak and semi-weak keys. In Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) (Vol. 263 LNCS, pp. 9–32). Springer Verlag. https://doi.org/10.1007/3-540-47721-7_2