Proceedings of the International School of Physics ''Enrico Fermi'' : Course LXXVI / ed. by J.R. Greening. Greening, J.R. Medical physics Health Physics 610.158 INM Including bibliographical references . New York : North-Helland, c1981. c1981. 1981 Text xvii, 521 p. : eng Proceedings ofthe International School of Physics ''Enrico Fermi'' Course 76