@book{21339,
	author = {Soffel, Michael  and Langhans, Ralf},
	title = {Space-Time Reference Systems},
	publisher = {Springer Berlin Heidelberg},
	year = {2013},
	series = {Astronomy and Astrophysics Library},
	address = {Heidelberg, Berlin},
	url = {http://doi.org/10.1007/978-3-642-30226-8}
}