I. Niebel

Analyzing the Spanish strip cipher by combining combinatorial and statistical methods

Christof Paar, Ingo Niebel, Gregor Leander, 2016, Cryptologia.

Learning Cryptanalysis the Hard Way: A Study on German Culture of Cryptology in World War I

Ingo Niebel, I. Niebel, 2018, HistoCrypt.