@book{20920,
	author = {D'Onofrio, Mauro  and Marziani, Paola },
	title = {Fifty Years of Quasars},
	publisher = {Springer Berlin Heidelberg},
	year = {2012},
	series = {Astrophysics and Space Science Library},
	address = {Heidelberg, Berlin},
	url = {http://doi.org/10.1007/978-3-642-27564-7}
}