David Kahn. The Geheimschreiber. Cryptologia, 3(4):210-214, 1979. [doi]
@article{Kahn79d,
title = {The Geheimschreiber},
author = {David Kahn},
year = {1979},
doi = {10.1080/0161-117991854089},
url = {http://dx.doi.org/10.1080/0161-117991854089},
researchr = {https://researchr.org/publication/Kahn79d},
cites = {0},
citedby = {0},
journal = {Cryptologia},
volume = {3},
number = {4},
pages = {210-214},
}