@book{25665,
	author = {Greening, J.R.},
	title = {Proceedings of the International School of Physics ''Enrico Fermi'' :},
	publisher = {North-Helland,},
	year = {c1981.},
	series = {Proceedings ofthe International School of Physics ''Enrico Fermi'' Course 76},
	address = {New York :}
}