@book{113729,
	author = {Williams, Roy H.  and Drew, Michael R. },
	title = {Pendulum :},
	publisher = {Vanguard Press,},
	year = {c2012.},
	address = {New York :},
	url = {http://www.loc.gov/catdir/enhancements/fy1306/2012289020-b.html}
}