ANCORA SULLE CASSEFORTI

Edward H. Smith. The Romance of the Lock. Scientific American , Vol. 130, No. 2 (february 1924), pp. 78-79, 142-143.

Albert A. Hopkins. Foiling the Burglar—III. Scientific American , Vol. 141, No. 3 (September 1929), pp. 226-228

Emory Chubb. Recent developments in the manufacture of safes and strong rooms. Journal of the Royal Society of Arts, Vol. 71, No. 3658 (december 29, 1922), pp. 109-117.