Radioactivity and radioactive substances / by Sir J.Chadwick; rev. and supplemented by J.Rotblat. Chadwick, James, Sir, 1891- Rotblat, J. Radioactivity. Radioactive substances. 539.752 CHR Includes index. London : Pitman, 1953. 1953. 1953 Text xv, 120 p.: eng