Papal Ciphers from the 16th to the 18th Century

Vatican ciphers are difficult to solve even with computer algorithms that can solve homophonic ciphers in an instant. This is because they used variable-length symbols written continusouly without a break, as I reported in "Variable-Length Symbols in Italian Numerical Ciphers" in 2017. I succeeded in solving three such ciphertexts found in the French archives, as I reported in "Identifying Italian ciphers from continuous-figure ciphertexts (1593)" (Cryptologia).
"Deciphering papal ciphers from the 16th to the 18th Century" by George Lasry, Beáta Megyesi, & Nils Kopal, now included in Volume 45 of Cryptologia, studied many ciphertexts in the Vatican archives systematically and identified no less than 16 keys. I should have mentioned this when the paper was published online in June 2020. Until now, I mentioned it in "Unsolved Historical Ciphers" only as a footnote to "New Vatican Challenges." Now, I mentioned it in a separate entry "Papal Ciphers from the 16th to the 18th Century."