Various watch-making and collectors books including; Dr A.L. Rawlings The Science of Clocks and Watches, 2nd. ed., London, 1948; T.P. Camerer Cuss, The Story of Watches, 1st. ed., 1952; J.W.Player, Watch Repairing, 3rd. ed., Dorchester, 1946; Grant Hood, Modern Methods in Horology, 1st. ed. Peoria, U.S.A., 1913,; E. Borer, Modern Watch Repairing and Adjusting, London, 1942; Henry B. Gried, The Watch Repairer's Manual, U.S.A., 1949.