@book{33199,
	author = {Lang, Kenneth R. and SpringerLink (Online service)},
	title = {A Companion to Astronomy and Astrophysics},
	publisher = {Springer New York,},
	year = {2006.},
	address = {New York, NY :},
	url = {http://dx.doi.org/10.1007/0-387-33367-3}
}