Discussion in London

Schlesinger G. 1926 “Normung des Gewindesystems” (Standardization of thread systems), D.I.N-Buch 2, Berlin, 2nd ed.

Berndt G. 1925 “Die Gewinde” (Threads, their development, measurement and tolerances), Julius Springer, Berlin. (Contains a full review of Whitworth, U.S. standard, Système Internationale, Thury, and other threads.).

Berndt G. 1929 “Die Deutschen Gewindetoleranzer” (German Thread Tolerances), Julius Springer, Berlin.