Dutch Codebreaking Activities during WWI

Florentijn van Kampen (2025), 'Dutch Cryptanalysis of Four American Diplomatic Codes in World War I' (HistoCrypt 2025) is interesting in describing Dutch codebreaking activities during WWI. Beside that, it presents examples of how code (as opposed to a cipher) can be broken. It is also valuable for me to show sources about the US State Department Codes. I updated "How to Break a Code (Not a Cipher)" and "Red and Blue: First Official Codebooks Adapted for Telegraphy" by mentioning these.