@book{619,
	title = {Physical science.},
	publisher = {Prentice Hall,},
	year = {2004.},
	series = {Science explorer, virginia.},
	address = {New York},
	edition = {Virginia ed.},
	url = {http://www.amazon.com/exec/obidos/ASIN/013190230X/chopaconline-20}
}