@book{117613,
	author = {Das, Ashok, and ebrary, Inc.},
	title = {Lectures on gravitation},
	publisher = {World Scientific,},
	year = {c2011.},
	address = {Hackensack, N.J. :},
	url = {http://site.ebrary.com/lib/rucke/Doc?id=10479685}
}