Leo Szilard, Helen S. Hawkins, G. Allen Greb, Gertrud Weiss Szilard (1987). “Toward a Livable World: Leo Szilard and the Crusade for Nuclear Arms Control”, p.25, MIT Press
1939 After an early experiment at Columbia University which proved the possibility of splitting the atom. Quoted in James B Simpson Simpson's Contemporary Quotations (1988).
Leo Szilard, Helen S. Hawkins, G. Allen Greb, Gertrud Weiss Szilard (1987). “Toward a Livable World: Leo Szilard and the Crusade for Nuclear Arms Control”, p.67, MIT Press