@book{104426,
	author = {Willoughby, David A. and ebrary, Inc.},
	title = {Horizontal directional drilling},
	publisher = {McGraw-Hill,},
	year = {c2005.},
	series = {McGraw-Hill civil engineering},
	address = {New York :},
	url = {http://site.ebrary.com/lib/strathmore/Doc?id=10180013}
}