@book{216484,
	author = {Hall, G. S. and ebrary, Inc.},
	title = {Symmetries and curvature structure in general relativity},
	publisher = {World Scientific,},
	year = {2004.},
	series = {World Scientific lecture notes in physics ;},
	address = {River Edge, NJ :},
	url = {http://site.ebrary.com/lib/strathmore/Doc?id=10082170}
}