@book{34507,
	author = {Grego, Peter. and SpringerLink (Online service)},
	title = {Venus and Mercury, and How to Observe Them},
	publisher = {Springer New York,},
	year = {2008.},
	series = {Astronomers' Observing Guides,},
	address = {New York, NY :},
	url = {http://dx.doi.org/10.1007/978-0-387-74286-1}
}