@article{JRAM_1964__213_150583,
     author = {Jack Levine},
     title = {Analysis of the {Case} n=3 in {Algebraic} {Cryptography} with {Involutory} {Key-Matrix} and {Known} {Alphabet.}},
     journal = {Journal f\"ur die reine und angewandte Mathematik},
     pages = {1--30},
     publisher = {mathdoc},
     volume = {213},
     year = {1964},
     zbl = {0124.11604},
     url = {http://geodesic.mathdoc.fr/item/JRAM_1964__213_150583/}
}